7 


TA 

405 

B32 


RESOLUTIONS 


OF    THE 


ions  held  at  Mil,  Dresden,  Berlin,  and  Vienna, 


FOR   THE 


PURPOSE  OF  ADOPTING  UNIFORM  METHODS  FOR  TESTING 

CONSTRUCTION  MATERIALS  WITH  REGARD  TO 

THEIR  MECHANICAL  PROPERTIES, 


BY 


J,  BAUSCHINGEE, 

PROFESSOR     IN     TH  E  TECHNICAL  H IGH   SCHOOL,   MUNICH. 


TRANSLATED    BY 

O.  M.  CARTER, 

CAPTAIN,  COUPS    OK    ENGINEERS,   U.  S.  A., 
AND 

K.  A.  GIESELER, 

UNITED    STATES    ASSISTANT    ENGINEER. 


WASHINGTON: 

GOVERNMENT    PRINTING    OFFICE. 

1896. 


RESOLUTIONS 


OF    THE 


Cooveofastidtl  at  Municti,  Dresden,  Berlin,  and  Vienna, 


FOR   THE 


PURPOSE  OF  ADOPTING  UNIFORM  METHODS  FOR  TESTING 

CONSTRUCTION  MATERIALS  WITH  REGARD  TO 

THEIR  MECHANICAL  PROPERTIES, 


BY 


J,  BAUSOHINGEE, 

PROFESSOR     IN     THE  TECHNICAL  HIGH  SCHOOL,   MUNICH. 


TRANSLATED  BY 

O.  M.  CARTER, 

CAPTAIN,  CORPS   OF   ENGINEERS,  U.  S.  A., 
AND 

E.  A.  GIESEUER, 

UNITED   STATES   ASSISTANT   ENGINEER. 


WASHINGTON: 

GOVERNMENT    PRINTING    OFFICE. 
189G. 


WAK  DEPARTMENT 
„ , .  .  Document  No.  J.. , 
OJfiwbf  the  C-kief  ef  Eh^neers. 


UNITED  STATES  ENGINEER  OFFICE, 

Savannah,  Ga.,  January  13,  1896. 

GENERAL:  I  have  the  honor  to  transmit  herewith  a  translation  from 
the  German  of  the  Resolutions  of  the  Conventions  held  at  Munich, 
Dresden,  Berlin,  and  Vienna,  for  the  Purpose  of  Adopting  Uniform 
Methods  for  Testing  Construction  Materials  with  Regard  to  their 
Mechanical  Properties.  The  resolutions  are  of  value,  and,  I  think, 
should  be  printed  for  distribution  to  the  officers  of  the  Corps  of 
Engineers. 

Very  respectfully,  your  obedient  servant, 

O.  M.  CARTER, 
Captain,  Corps  of  Engineers. 
Brig.  Gen.  WM.  P.  CRAIGHILL, 

Chief  of  Engineers,  U.  S.  A. 

[First  indorsement.] 

OFFICE  CHIEF  OF  ENGINEERS, 

U.  S.  ARMY, 

January  18, 1896. 

Respectfully  submitted  to  the  Secretary  of  War,  with  the  recom- 
mendation that  the  work  be  printed  at  the  Government  Printing  Office 
for  the  use  of  the  Corps  of  Engineers,  and  that  300  copies  be  obtained 
on  the  usual  requisition. 

W.  P.  CRAIGHILL, 
Brig.  Gen.,  Chief  of  Engineers. 

[Second  indorsement.] 

WAR  DEPARTMENT, 

January  21,  1896. 

Approved  as  recommended  by  the  Chief  of  Engineers. 
By  order  of  the  Secretary  of  War : 

JOHN  TWEEDALE, 

Chief  Cleric. 


M46822 


CONTENTS. 


Page- 
Introduction  _ 7 

I.  General  provisions 11 

1.  Requirements  of  testing  machines 11 

2.  Arrangements  for  mounting  test  pieces 11 

3.  Uniform  testing  machine 11 

4.  Data  concerning  machines  and  methods,  to  bo  given  when  commu- 

nicating results 11 

5.  Data  in  regard  to  test  [pieces,  to    be  given  when  communicating 

results , 11,12 

6.  Limits  of  exactitude  .., 12 

7.  Influence  of  time  on  tests  of  strength 12 

8.  Materials  should  be  tested  for  the  class  of  strains  occurring  during 

actual  use 12 

9.  Impact  tests  for  material  subjected  to  shock  when  in  use 13 

10.  Standard  impact  machine 13 

II.  Tests  of  wrought  iron  and  steel 16 

A.  Rails,  Nos.  1-6 16 

B.  Axles,  Nos.  1-3 17 

C.  Tires,  Nos.  1-3 17 

D.  Multiple  or  piece  tests,  Nos.  1-3 17 

E.  Wrought  iron  for  bridges,  Nos.  1-3 18 

F.  Low  or  mild  steel  for  bridges,  Nos.  1-2 18 

G.  Wrought  iron  for  boiler  work,  Nos.  1-3 18 

II.  Low  or  mild  steel  for  boiler  work,  Nos.  1-5 18 

The  place  at  which,  and  the  manner  in  which,  test  pieces  should 

be  cut  out  of  boiler  plates 19 

I.  Wire,  Nos.  1-3 20 

K.  Wire  rope,  Nos.  1-2 20 

L.  Measurements  to  be  made  in  tension  tests,  Nos.  1-5 21 

M.  Form  of  test  pieces  for  tension  tests,  Nos.  1-7 21 

N.  Bending  tests 23 

III.  Tests  of  cast  iron,  Nos.  1-7 24 

IV.  Tests  of  copper,  bronze,  and  other  metals 25 

V.  Tests  of  wood,  Nos.  1-7 26 

VI.  Tests  of  shipbuilding  materials,  Nos.  1-2 28 

VII.  Tests  o f  stone 28 

A.  Stone  in  general ;  resistance  to  boring  or  quarrying,  Nos.  1-5 28 

B.  Building  stone 30 

a.  Natural  building  stone,  Nos.  1-11 30 

/?.  Artificial  build  ing  stone 32 

aa.  Bricks,  Nos.  1-7 32 

j8/3.  Roofing  tiles,  Nos.  1-8 34 

C.  Paving  and  ballast  material,  natural  and  artificial,  Nos.  1-11 35 

D.  Tests  of  preservatives  for  natural  and  artificial  stone 36 

5 


Page. 

VIII.  Tests  of  hydraulic  binding  media 37 

A.  General  remarks,  Nos.  1-2 37 

B.  Nomenclature,  Nos.  1-6 38 

C.  Tests 38 

1.  Weight 38 

2.  Fineness  of  grain 38 

3.  Conditions  of  setting 39 

4.  Constancy  of  volume 40 

5.  Tests  of  strength 42 

6.  Adhesive  strength 44 

7.  Density 44 

8.  Action  of  sea  water  on  hydraulic  binding  media 44 

New  problems 44 


INTEODUOTIOISr. 


*  «•  * 
I  •  V 


It  is  universally  acknowledged  at  the  present  day  that  tests  of  mate- 
rials of  construction  with  regard  to  their  mechanical  properties  are  com- 
parable with  one  another  and  give  practical  results  only  when  they  are 
made  according  to  uniform  methods.  The  recognition  of  the  necessity 
for  such  uniformity  brought  about  as  early  as  1876  the  adoption  of 
u Standard  rules  for  furnishing  and  testing  Portland  cement"  by  the 
Association  of  German  Portland  Cement  Manufacturers,  also  the 
"Drafts  of  specifications  for  furnishing  axles,  tires,  and  rails  of  iron 
and  steel"  which  were  recommended  in  1879  by  the  Association  of 
German  Eailway  Administrations  for  adoption  by  its  members.1 

Those  first  attempts  at  unifying  the  methods  of  testing  emanated, 
however,  from  too  narrow  sources,  from  manufacturers  only  on  the  one 
hand  and  from  consumers  only  on  the  other,  and  their  suggestions 
were  naturally  governed  by  their  respective  interests ;  at  least  this  was 
asserted  to  be  the  case.  Each  of  those  agreements,  moreover,  had  the 
inconvenience  of  relating  to  only  a  single  group  of  materials;  further- 
more, they  were  not  confined  to  methods  of  testing,  but  specified  con- 
ditions to  which  materials  should  conform  when  tested  according  to 
prescribed  methods. 

The  convention  held  in  the  autumn  of  1884  at  Munich,  composed  of 
representatives  of  all  the  technical  professions,  with  the  aim  of  unifying 
the  methods  of  testing  the  principal  materials  of  construction,  neglect- 
ing entirely  any  classification  of  those  materials,  was  consequently  jus- 
tified. That  convention  succeeded  in  agreeing  upon  quite  a  series  of 
important  questions,  while  a  certain  number  of  others  were  referred  to 
a  permanent  committee,  which  thoroughly  discussed  them,  first  in  writ- 
ing and  then  orally,  at  its  two  sessions  held  in  Munich  on  the  21st  and 
22d  of  September,  1885,2  and  which  finally  submitted  a  report  upon  the 
results  of  its  labors  to  a  second  convention,  held  in  Dresden  on  the  20th 
and  21st  of  September,  1886. 

The  latter  convention  accepted  almost  all  of  the  propositions  which 

!The  properties  of  iron  and  steel.  Seventh  supplementary  volume  to  "Organ  fur 
die  Fortschritte  des  Eisenbahnwesens."  Wiesbaden,  1880. 

2A  detailed  report  011  the  discussions  of  the  Munich  convention  and  the  perma- 
nent committee  appointed  by  it  is  contained  in  No.  XIV  of  "Mittheilungen  aus 
dem  mechanisch-technischen  Laboratorium  der  technischen  Hochschule/'  Muenchen. 
(Munich,  Th.  Ackcrmann.) 

7 


8 

were  submitted  to  it,  but  charged  a  second  permanent  committee  with 
the  study  of  a  series  of  questions  which  had  not  yet  been  taken  hold  of  or 
agreed  upon,  with  instructions  to  render  a  report  to  a  third  convention, 
which  was  to  meet  on  the  19th  and  20th  of  September,  1890,  in  Berlin. 
At  that  convention  resolutions  were  adopted  with  regard  to  a  certain 
-number  of  propositions,  while  others,  together  with  certain  new  ques- 
tions, wore  r&ferrexlto  a  third  permanent  committee,  charged  with  pre- 
;..  ££n$ing.a.:?epprt>to  a  fourth  convention,  which  was  to  be  held  at  Vienna 
•  oil  th'e24th  ab4'25th  of  May,  1893.  At  that  convention  an  agreeme.it 
was  reached  again  011  only  a  portion  of  the  proposed  resolutions,  and 
the  others  were  referred,  with  a  great  number  of  new  questions,  to  a 
fourth  permanent  committee,  the  executive  of  which  was  at  the  same 
time  charged  with  the  preparation  of  a  memoir  containing  all  of  the 
resolutions  adopted  up  to  that  date,  as  well  as  all  of  the  questions  upon 
which  no  agreement  had  been  reached,  in  the  same  way  as  had  been 
done  for  the  first  two  conventions  in  a  pamphlet  entitled  "Resolutions 
of  the  Conventions  held  at  Munich  and  Dresden,"  etc. 

The  hope  expressed  in  that  pamphlet  that  its  publication  might  aid  in 
sustaining  tbe  eiforts  already  put  forth,  and  at  the  same  time  induce  those 
who,  up  to  that  date,  had  not  interested  themselves  in  such  questions 
to  participate  in  the  future,  has  been  fulfilled  in  a  very  gratifying  way. 
Not  only  has  there  been  an  increase  in  the  number  of  delegates  from 
countries  already  represented  (Germany,  Austria-Hungary,  Switzer- 
land, Russia),  but  delegates  have  come  from  other  countries  (France, 
America,  Norway,  Holland,  Italy,  Spain),  so  that  the  conventions  have 
assumed  a  truly  international  character.  With  the  aim  of  developing 
this  movement  still  more  it  should  be  remembered  that  each  conference 
is  a  reunion  at  which  all  members  can  exchange  freely  their  opinions 
as  to  the  best  methods  to  be  employed  for  testing  as  to  its  mechanical 
properties  a  certain  material  intended  for  a  certain  purpose.  Votes 
and  resolutions  have  no  other  aim  than  to  bring  out  the  methods  of 
testing  which  the  majority  of  the  members  prefer.  In  conformity  with 
the  first  resolution  of  the  first  conference,  "  deliberations  are  to  be 
free  and  resolutions  not  obligatory."  There  is  nothing  to  prevent  a 
question  which  has  been  acted  upon  in  a  preceding  conference  from 
being  taken  up  again,  discussed,  and  submitted  to  a  new  vote.  The 
methods  of  testing  can  not  remain  unchangeable;  they  must  progress 
with  our  knowledge  of  the  properties  of  the  materials  that  we  employ, 
with  the  improvements  brought  about  in  the  production  of  those 
materials,  with  the  employment  of  new  materials,  etc.  It  is  then  neces- 
sary that  those  who  are  occupied  with  tests  of  construction  materials — 
whether  from  a  scientific  point  of  view  or  because  they  are  making  or 
using  such  materials — should  meet  from  time  to  time  to  exchange 
opinions,  to  mutually  instruct  one  another,  and  from  such  deliberations 
to  agree  upon  methods  of  testing  that  they  judge  to  be  the  best,  or  at 
least  that  the  majority  among  them  find  to  be  the  most  suitable  for  the 
time  being. 


Present  methods  of  communication  Lave  so  nearly  eliminated  the 
dividing-  line  between  all  civilized  and  manufacturing  countries  that 
the  unification  of  methods  of  testing  will  have  little  value  if  it  is  limited 
to  a  few  countries.  The  recognition  of  the  necessity  for  international 
agreement  has  led  the  conferences,  which  were  participated  in  at  the 
beginning  only  by  Germany  and  some  immediately  neighboring  coun- 
tries, to  become  more  and  more  international  in  character. 

By  a  decree  of  the  9th  of  November,  1891,  the  President  of  the  French 
Republic  created  a  u  Commission  des  methodes  d'essai  des  materiaux 
de  construction,"  whose  object,  as  its  name  indicates,  is  the  same  as 
that  of  the  conventions  of  Munich,  Dresden,  Berlin,  and  Vienna,  and 
their  permanent  committees.  Such  national  institutions  have  cer- 
tainly two  great  advantages;  they  have,  at  least  at  home,  greater 
authority  and  it  is  easier  for  them  than  for  private  societies  to  procure 
funds  for  necessary  experimental  research.  It  is  evident  that  they  lack 
an  international  character,  but  that  could  be  obtained  by  a  suitable 
agreement  between  the  different  national  commissions;  but  then  the 
advantages  before  mentioned  resulting  from  the  private  character  of 
those  conferences  would  be  lost.  On  the  other  hand,  the  advantages 
resulting  from  governmental  support  could  very  well  be  combined  with 
those  inherent  in  conventions  such  as  have  been  held  up  to  the  present, 
if  the  permanent  committees,  working  in  the  interval  between  the  ses- 
sions of  the  conventions,  were  composed  as  well  of  representatives  of 
private  industry  as  of  technical  government  delegates  and  delegates 
from  technical  associations  and  societies. 

To  effect  those  aims  the  president  of  the  fourth  permanent  committee 
elected  by  the  convention  at  Vienna  was  instructed  to  make  every 
effort  in  order  that  the  greatest  possible  number  of  technical  associa 
tions  and  societies  should  send  delegates  who  would  thus  participate 
in  the  labors  of  the  committee. 

In  the  following  compendium  the  resolutions  passed  so  far  are  printed  in  ordinary 
ronian  type;  a  short  statement  of  the  reasons  for  their  adoption  is  printed  in  small 
roman  type,  and  questions  still  open  to  discussion  are  printed  in  italics. 


UNIFORM  METHODS  FOR  TESTING  CONSTRUCTION 
MATERIALS  WITH  REGARD  TO  THEIR  MECHANICAL 
PROPERTIES. 


I.  GENERAL  PROVISIONS. 

1.  All  machines  for  testing  materials  should  be  arranged  in  such  a 
way  that  their  adjustment  can  be  verified  with  ease  and  certainty. 

Their  construction  must  be  such  that  with  proper  handling  sudden, 
shock-like  action  of  the  load  is  excluded  as  much  as  possible.  Machines 
acting  by  hydraulic  pressure,  as  well  as  those  acting  by  means  of  a 
screw,  conform  to  this  condition.  For  practical  purposes  no  separate 
attachment  making  the  machine  self-acting  is  required. 

2.  The  arrangement  for  securing  the  test  piece  in  the  machine  must 
be  such  as  to  allow  as  much  as  possible  uniform  distribution  of  strain 
in  the  cross  section. 

To  obtain  this  the  following  is  required: 

(a)  For  pressure  tests — 

(a)  One  of  the  two  pressure  plates  must  move  easily  and  freely  in 
all  directions. 

(I)  The  pressure  surfaces  of  the  test  pieces  must  be  as  nearly  plane 
and  parallel  as  possible,  and  with  this  object  in  view  should  be  planed 
or  turned  whenever  the  material  admits  of  either  of  those  operations. 

(/?)  For  tensile  tests — 

There  shall  be  freedom  and  ease  of  movement  for  adjustment  of  posi- 
tion at  commencement  of  tension.  Experience  shows  that  this  con- 
dition is  obtained:  In  the  case  of  round  bars,  by  means  of  spherical 
bearings;  in  the  case  of  flat  bars,  by  means  of  slot  and  bolt  (one  slot 
and  one  bolt  on  each  side),  or  milled  ends  and  corresponding  wedges. 

Serrated  wedges  that  cut  into  the  test  pieces  should  never  be  used. 

3.  It  is  impossible  to  recommend  for  practical  use  a  uniform  appara- 
tus for  tests  of  strength;  it  may  be  stated,  however,  that  a  number  of 
well-known  machines  are  more  or  less  well  adapted  for  their  particular 
purposes. 

4.  In  communicating  results  of  tests  there  should  be  given  such  data 
in  regard  to  the  machines  and  methods  employed  as  are  required  to 
enable  one  to  judge  of  the  value  of  the  tests. 

5.  Whenever  possible,  results  of  tests  should  be  accompanied  by 
information  as  to  whence  the  test  piece  came,  by  a  microscopical  or 
a  chemical  examination,  or  both,  by  data  relating  to  the  manner  of 
its  manufacture,  and  other   known  physical,  chemical,  or  technical 
properties. 

11 


12 

In  the  case  of  tests  intended  mainly  for  practical  purposes  it  will  rarely  be  prac- 
ticable to  include  sucb  complementary  information ;  still,  for  the  sake  of  comprehen- 
sive results,  its  acquisition  is  always  desirable,  and  it  should  never  be  neglected  in 
the  case  of  scientific  investigations. 

6.  Regarding  the  required  degree  of  exactitude  of  testing  machines 
and  of  the  results  of  tests  of  materials,  the   following   should  be 
observed : 

(a)  To  economize  time,  the  limit  of  exactitude  in  measuring  changes 
of  force  and  of  form  should  not  be  extended  beyond  the  limit  of  un- 
avoidable errors  and  of  imperfection  of  materials. 

(b)  In  scientific  experiments  it  is  obvious  that  the  highest  possible 
degree  of  precision  should  be  sought. 

(c)  In  publishing  results  of  tests  the  degree  of  precision  attained 
should  be  given,  or  data  should  be  furnished  from  which  an  opinion  in 
regard  to  it  can  be  formed. 

Present  experience  justifies  the  following  proposition: 

(d)  In  the  case  of  metals  when  test  bars  of  standard  dimensions  are 
used  (such  as  are  described  below  under  II  M  and  under  IV)  the  fol- 
lowing degrees  of  exactitude  are  sufficient:     Strains,  at  the  limit  of 
rupture,  should  be  measured  to  tenths    of  a  kilogram    per   square 
millimeter;  elongation  at  rupture  should  be  measured  to  tenths  of  1 
per  cent;  reduction  of  cross-sectional  area  should  be  measured  to  the 
nearest  full  per  cent. 

In  figures  given  according  to  this  schedule  the  last  digit  is  generally 
unreliable;  consequently  it  is  useless  to  add  any  further  decimals.  In 
order  to  conform  as  far  as  practicable  to  the  above  degrees  of  exacti- 
tude, length  and  cross-sectional  dimensions  should  be  determined  to 
tenths  of  millimeters. 

7.  According  to  Fischer  and  Hartig,  time  exercises  an  undoubted 
influence  on  tests  ot  strength;  still  other  experiments  made  since  then 
have  demonstrated  that  there  is  not  at  present  any  sufficient  reason  to 
warrant  a  demand  for  any  fixed  velocity  of  stretching  in  testing  the 
principal  materials  of  construction,  viz,  iron  in  all  its  forms,  copper  and 
bronze  (see  Bauschinger's  experiments  in  No.  20  of  his  u  Mittheiluugen, 
etc."). 

8.  Materials  should  be  tested  for  that  class  of  strains  to  which  they 
will  be  statically  subjected  in  actual  use. 

The  quality  of  a  material  per  se  is  the  sum  of  its  mechanical  properties.  So  long  as 
we  are  ignorant  of  the  relations  existing  between  these,  and,  therefore,  are  unable 
to  judge  from  one  or  more  of  them  as  to  the  nature  of  the  rest — which  we  are  far 
from  being  able  to  do  at  present— so  long  will  it  remain  impossible  to  foretell  the 
behavior  of  a  material  under  different  conditions  of  strain,  merely  from  a  determi- 
nation of  one  or  several  of  its  properties,  and  so  long  will  it  therefore  remain 
necessary  to  test  materials  in  regard  to  the  mechanical  properties  required  in  actual 
use.1 

JFor  an  ample  demonstration  of  this  resolution,  see  "Mittheilungen,"  etc.,  No.  14, 
pp.  156-160. 


13 

9.  All  materials  which  will  be  submitted  to  shocks  when  in  actual 
use  should  be  tested  by  impact,  in  order  to  study  fully  their  qualities. 

10.  Tests  by  impact  should  be  made  by  a  standard  impact  testing- 
machine,  to  be  constructed  as  follows: 

(a)  It  is  not  considered  necessary  to  prescribe  the  complete  construc- 
tion of  a  standard  impact-testing  machine,  but  merely  to  give  accurate 
instructions  in  regard  to  all  of  those  parts  which  can  possibly  exercise 
any  influence  on  the  results  of  tests.     It  is  recommended  that  the 
frame  of  the  machine  should  be  made  of  iron. 

It  was  thought  necessary  to  take  into  consideration  existing  apparatus,  the  essen- 
tial parts  of  most  of  which  conform  to  the  following  requirements : 

(b)  Every  standard  impact    testing  machine   should    be  officially 
gauged. 

It  is  not  impossible  that  a  machine  constructed  with  the  greatest  care  may  give 
false  results  on  account  of  unforeseen  influences. 

(c)  Iii  accordance  with  the  requirements  of  German  railway  admin- 
istrations, and  considering  that  impact  testing  machines  should  be 
housed,  the  normal  weight  of  hammer  should  be  1,000  kilograms,  500 
kilograms  being  allowed  in  exceptional  cases. 

(d)  The  hammer  may  be  made  of  cast  iron,  of  cast  or  of  wrought  steel; 
its  form  should  be  such  as  to  have  the  center  of  gravity  as  low  down  as 
possible.     The  face  of  the  hammer  should  be  made  of  wrought  steel  and 
secured  by  means  of  dovetail  and  wedges,  ex- 
actly centrally  to  its  vertical  axis.    The  fact 

that  this  requirement  has  been  complied  with 
should  be  indicated  by  special  marks.  The 
center  of  gravity  of  the  hammer  must  coincide 
with  the  center  line  of  the  leads.  This  line 
should  be  indicated  by  special  marks  on  the 
anvil  or  the  anvil  block.  '*"  Fia 

(e)  The  guided  length  of  hammer   should 

be  more  than  twice  the  clear  width  between  guides.  The  leads  should 
be  made  of  metal,  for  instance  of  railroad  iron,  the  hammer  being  allowed 
but  little  play  between  them.  Lubrication  of  the  leads  with  plumbago 
is  recommended. 

(/)  Shock  machines  must  be  provided  with  an  apparatus  allowing 
the  hammer  to  be  set  securely  at  the  desired  height.  The  detaching 
apparatus  ought  not  to  produce  any  wedging  of  the  hammer  in  the 
guides;  therefore  the  part  carrying  the  detaching  apparatus  should  be 
well  guided.  The  point  of  suspension  should  be  on  the  same  vertical 
as  the  center  of  gravity  of  the  hammer,  and  there  should  be  placed 
between  the  detaching  device  and  the  hammer  a  flexible  piece  of  short 
length,  for  example  a  chain  or  a  cord.  The  detaching  device  officially 
prescribed  in  Eussia  and  represented  by  the  sketch  herewith  (fig.  1)  is 
to  be  recommended. 

(g)  With  a  constant  height  of  fall  an  automatic  detaching  device  is 
recommended. 


14 

(7i)  The  bearings  for  the  test  pieces  should  be  attached  rigidly  to  the 
anvil  block — for  instance,  by  the  aid  of  wedges. 

The  bearing  blocks  should  be  made  to  form  as  nearly  as  possible  one  single  mass 
with  the  anvil  block. 

(i)  The  weight  of  the  anvil  block  should  be  at  least  equal  to  ten  times 
that  of  the  hammer. 

Since  comparative  tests  which  have  been  made  with  a  ballistic  apparatus  and  an 
ordinary  hammer  have  proved  that  with  an  anvil  mass  four  times  heavier  than  the 
hammer  the  results  are  sufficiently  concordant  (see  Kick  on  the  Law  of  Proportional 
Resistances),  one  may  be  sure  that  with  a  total  anvil  mass  ten  times  heavier  than 
the  striking  hammer  the  results  will  always  be  comparable  with  one  another. 

(k)  The  foundations  should  not  be  elastic;  they  should  be  built  of 
solid  masonry  and  have  dimensions  determined  by  the  nature  of  the 
ground. 

(?)  The  striking  surface  of  the  hammer  should  always  be  plane;  there- 
fore, in  testing  rails,  axles,  and  tires  use  should  be  made  of  interposed 
pieces  dressed  to  the  required  shape  and  having  plane  upper  surfaces. 
The  interposed  pieces  should  be  as  light  as  possible. 

The  same  hammer  with  plane  striking  surface  is  recommended  in  all  cases,  for  the 
sake  of  simplicity  of  preparation  as  well  as  in  consideration  of  the  correction  of 
hammer  weight  according  to  o  and  p. 

(m)  The  results  of  previous  experiments  are  not  conclusive  enough 
to  determine  the  form  of  the  supports  and  of  the  pieces  destined  to 
receive  the  shock  or  blow.  It  is  recommended,  however,  that  there 
should  be  given  in  reports  of  tests,  or  when  exhibiting  tested  samples, 
exact  information  regarding  the  forms  employed. 

(n)  More  confidence  can  be  placed  in  machines  whose  height  of  fall 
is  not  greater  than  6  meters  than  in  those  with  a  greater  height  of  fall. 
It  is  recommended,  therefore,  that  that  height  should  not  be  exceeded 
in  new  constructions.  Where  a  stronger  blow  is  desired,  a  hammer 
weighing  1,000  kilograms  should  be  employed. 

Machines  with  a  height  of  fall  of  6  meters  can  bo  housed  easier  and  can  be  con- 
structed with  more  reliability  than  higher  ones.  Their  parts  are  also  less  susceptible 
of  being  disarranged. 

(o)  The  impact  work  produced  by  the  hammer  is  the  product  of  its 
effective  weight  by  its  height  of  fall.  Its  total  weight  should  be  regu- 
lated so  that  its  effective  weight  amounts  to  some  round  figure — for 
instance,  500  kilograms. 

The  results  are  comparable  with  one  another  only  when  the  loss  of  living  force  due 
to  friction  is  eliminated. 

(p]  To  determine  the  effective  weight  of  the  hammer,  the  following 
methods  are  employed : 

(a)  A  spring  balance  is  placed  between  the  hammer  and  its  lifting 
rope,  and  the  effective  weight  is  read  during  slow  descent;  there  is 
thus  obtained  the  weight  of  the  hammer  less  the  friction.  The  upward 
movement  furnishes  the  same  weight  augmented  by  the  friction. 


15 

(ft)  The  weight  of  the  hammer  can  be  deduced  also  from  the  effect 
produced,  with  a  given  height  of  fall,  on  a  centrally  mounted  standard 
cylinder,  made  of  best  stay-bolt  copper,  of  a  shape  and  weight  still  to 
be  determined. 

(q)  These  standard  cylinders  should  also  be  used  to  compare  impact 
machines  with  one  another  and  to  gauge  them. 

The  Mechanical  Testing  Institute  at  Charlottenburg  has  already  made  such  com- 
parative tests,  and  no  doubt  will  willingly  take  charge  of  others  if  it  is  requested  so 
to  do. 

(r)  Impact  machines  which  have  a  work  due  to  friction  greater  than  2 
per  cent  of  their  useful  work  should  be  rejected. 

In  order  to  have  conclusive  shock  tests  there  should  be  employed  only  faultless 
machines ;  those  that  are  badly  constructed  or  badly  kept  up  must  not  be  used. 

(*)  The  standard  impact  testing  machine  is  destined  principally  for 
the  testing  of  whole  pieces,  such  as  rails,  axles,  tires,  springs,  etc. 

The  testing  of  pieces  specially  prepared  for  shock  trials  is  certainly  of  great  inter- 
est, but  principally  of  a  scientific  one  only,  and  therefore  it  is  not  considered,  neces- 
sary at  present  to  give  rules  for  the  construction  of  a  special  small  impact  machine 
and  for  the  methods  of  conducting  such  tests. 

(t)  The  vertical  position  of  the  guides  and  the  proper  location  of  the 
hammer  between  the  guides  should  be  rigorously  controlled.  The  ver- 
tical projection  of  the  center  of  gravity  of  the  hammer  on  the  anvil's 
surface  should  be  marked  on  the  anvil,  and  whether  the  test  piece  is 
properly  placed  in  the  vertical  of  the  center  of  gravity  of  the  hammer, 
and  whether  its  placing  may  not  cause  pinching  or  torsional  deforma- 
tion should  be  verified  previous  to  every  blow. 

(u)  The  work  done  by  a  hammer  within  very  wide  limits  depending 
only  on  the  product  of  its  fall  by  its  effective  weight,  and  not  on  one  of 
those  factors  individually,  it  is  recommended  that  the  metric  ton  should 
be  taken  as  the  unit  and  that  such  an  arrangement  should  be  made  as 
will  insure  the  product  always  being  a  multiple  of  500.  Instead  of 
graduating  the  divisions  on  the  scale  to  meters  they  will  be  divided 
into  metric  half  tons. 

(v)  It  is  recommended  that  sliding  scales  should  be  used  in  order  that 
the  zero  of  the  graduation  may  always  be  set  according  to  the  height  of 
the  test  piece. 

(w)  The  determination  within  a  millimeter  of  the  deflection  by  impact 
of  test  pieces  resting  on  supports  from  1  to  1£  meters  apart,  is  so  far 
considered  sufficiently  exact. 

(x)  To  facilitate  comparison  of  the  results,  it  is  recommended  that 
all  particulars  of  the  tests  should  be  given — for  example,  the  order  in 
which  the  blows  of  the  hammer  were  given,  whether  there  was  any 
interruption  of  the  test,  and  whether  the  test  pieces  were  reversed  or 
not,  also  all  the  phenomena  observed  during  the  test. 

(y)  The  permanent  commission  should  study  the  new  propositions  con- 
cerning the  construction  of  impact  machines  and  talce  especial  pains  to  col- 


16 

lect  the  results  of  all  experiments  made  in  regard  to  the  conduct  of  impact 
tests,  in  order  to  utilize  them  for  devising  a  uniform  method  of  testing. 

A  drawing  of  an  impact  machine  designed  by  Engineer  Schmitz  of 
Vienna  and  fulfilling  all  of  the  above  conditions  has  been  referred  to 
the  committee  for  its  further  study. 

II.  TESTS  OF  WROUGHT  IRON1  AND  STEEL. 
A.  RAILS. 

1.  Rails,  for  reasons  of  safety  and  in  accordance  with  the  resolution 
under  Heading  I,  No.  9,  should  be  tested  by  the  shock  method  by  means 
of  suitable  technical   devices.     (Standard   impact    machines;   see  I, 
No.  10.) 

2.  If  further  information  concerning  the  naiure  of  the  metal  is  desired 
tension  tests  will  be  made. 

3.  Finally,  rails  should  be  subjected  to  transverse  tests  by  a  static 
load,  and  in  two  ways;  up  to  permanent  set  in  order  to  determine  the 
elasticity,  and  by  means  of  heavy  loads  beyond  the  limit  of  elasticity 
in  order  to  determine  the  greatest  permanent  deflection. 

Members  of  the  Munich  convention  have  nearly  unanimously  recognized  that  for 
rails  tension  tests  alone  are  not  conclusive  enough.  Professor  Tetmajer  has  given 
plain  evidence  of  this  in  mentioning  contradictions  which  have  been  found  on  Fin- 
nish, Swiss,  and  French  railways  between  the  results  of  tension  tests  and  the  results 
obtained  in  service.  Those  contradictions  arise  from  the  fact  that  in  the  first  place 
rails  in  actual  service  are  strained  by  shock,  and  in  the  second  place  that  the  tension 
test  relates  only  to  a  small  part  of  the  cross  section ;  there  is,  therefore,  reason  for 
attaching  more  importance  to  shock  and  transverse  tests,  provided  they  are  made 
with  well-designed  apparatus,  the  shock  tests  especially  being  made  by  means  of 
standard  impact  testing  machines;  but  as  those  tests  do  not  furnish  as  many  indica- 
tions concerning  the  nature  of  the  metal  as  do  tension  tests,  especially  when  the 
latter  are  supplemented  by  chemical  analysis,  there  is  reason  to  maintain  that  ten- 
sion tests  should  be  employed  as  long  as  their  deductions  may  be  useful,  which  will 
probably  be  the  case  for  a  long  time. 

4.  Tension  tests  should  be  made  on  pieces  rectangular  in  section  and 
taken  from  the  exterior  fibers  of  the  rail. 

One  cause  of  doubt  regarding  the  results  of  tension  tests  arises  from  the  fact  that 
up  to  the  present  the  round  bars  used  for  the  tests  were  taken  from  the  center  of 
the  head  of  the  rail  so  that  the  libers  subjected  to  the  greatest  strains,  that  is,  the 
exterior  ones — the  ones  located  at  the  wearing  surface  and  at  the  seat  of  the  rail — 
were  not  submitted  to  the  test.  But  in  the  case  of  cast  steel,  these  are  the  very 
parts  containing  the  dangerous  blowholes  due  to  silica,  which  always  gather  near 
the  surface  of  the  ingots.  It  should  be  remarked,  on  the  other  hand,  that  in  the 
interior  of  ingots  of  pure  manganese  steel  there  is  a  /one  of  blowholes  which  may 
have  an  unfavorable  influence  on  the  tension  test,  but  not  on  the  rail  itself,  and 
which  may  therefore  give  rise  to  erroneous  conclusions. * 

1  The  term  "  wrought  iron  "  is  here  used  as  distinguished  from  "  cast  iron,"  and  is 
intended  to  comprise  "'wrought  iron"  proper  and  "mild  steel." 

2  For  details  see  "  Mittheilungen  der  Eidgenossicheii  Festigkeitsaustalt,"  No.  3, 
pp.  42-53. 


17 

5.  The  search  for  methods  of  test  suitable  for  determining  the  wear 
on  rails  and  tires  resolves  itself  into  a  search  for  methods  suitable  for 
determining  the  resistance  to  wear.    At  all  events  it  is  certain — 

(a)  That  the  resistance  to  wear  can  not  be  determined  by  an  experi- 
mental process. 

(6)  That  the  test  of  the  resistance  to  wear  should  be  made  under  con- 
ditions approaching  as  closely  as  possible  those  to  which  the  metal  will 
be  subjected  during  service. 

On  account  of  its  difficulty  this  question  is  for  the  present  set  aside. 

6.  The  investigation  relative  to  the  influence  of  different  kinds  of 
tires  on  the  wear  of  rails  should  be  considered  as  a  special  study  per- 
taining to  the  administration  of  railroads. 

B.  AXLES. 

1.  The  ends,  as  well  as  the  bodies,  of  axles  should  be  subjected  to 
shock  tests. 

2.  When  further  information  regarding  the  nature  of  a  material  is 
desired  tension  tests  should  also  be  made. 

3.  Axles  need  not  be  subjected  to  transverse  tests. 

C.  TIKES. 

1.  Tires  should  be  submitted  to  shock  tests  in  the  same  manner  as 
axles  and  rails. 

2.  Tension  tests  should  be  made  if,  as  above,  further  information  in 
regard  to  the  nature  of  the  material  is  desired. 

3.  The  hammering  test  is  not  necessary. 

D.  MULTIPLE  OR  PIECE  TESTS. 

1.  There  should  be  collected  as  much  information  as  possible  for  the 
purpose  of  devising  standard  rules  for  multiple  or  piece  tests  (test  of  each 
piece  in  a  lot). 

2.  In  deciding  upon  standard  rules  for  impact  testing  machines  and 
machines  for  tests  of  strength  there  should  be  kept  in  view  the  possibility 
of  making  multiple  or  piece  tests. 

3.  Not  only  axles  should  be  thought  of  in  this  connection,  but  all  con- 
struction material  of  steel  and  iron. 

The  multiple  or  piece  test,  whicli  consists  in  testing  rapidly  by  a  single  shock,  for 
example,  each  piece  of  a  lot,  in  such  a  way  as  not  to  injure  it,  certainly  offers  more 
of  a  guaranty  than  that  which  consists  in  testing  so  many  per  cent  of  the  pieces  of 
a  lot.  It  has  been  adopted  for  a  long  time  for  springs,  chains,  pipes,  steam  pipes, 
boiler  tubes,  etc.  It  has  given  good  results  in  Austria,  where  it  has  been  used  in  a 
number  of  cases  for  axles.  It  must,  however,  be  recognized  that  that  method  otters 
great  difficulties  for  the  buyer  as  well  as  for  the  seller,  but  those  difficulties  can  be 
overcome  by  the  study  and  adoption  in  practice  of  a  well-suited  mode  of  test.  The 
only  experience  available  so  far  in  regard  to  multiple  testa  has  been  gathered  at 
Witkowitz,  with  axles  only,  and  has  lately  led  to  abandoning  this  method  of  test. 
It  is  desired,  however,  that  more  experience  should  be  gathered. 
10389 2 


18 

E.  WROUGHT  IKON  FOR  BRIDGES. 

1.  Wrought  iron  entering  into  the  construction  of  bridges  should  be 
submitted  to  tension  tests,  and  also 

2.  To  bending  tests,  both  hot  and  cold,  over  a  mandril  25  mm.  in 
diameter,  by  means  of  a  slowly  working  mechanical  contrivance. 

The  exact  conditions  that  this  contrivance  should  fulfill  are  given 
hereafter  under  N. 

3.  Those  two  tests  being  sufficient,  there  is  no  necessity  of  making 
tests  for  flattening  and  rupture. 

F.  Low  OR  MILD  STEEL  FOR  BRIDGES. 

1.  Low  steel  entering  into  the  construction  of  bridges   should  be 
submitted,  like  wrought  iron,  to  tension  tests. 

2.  It  should  also  be  submitted  to  bending  tests,  both  hot  and  cold, 
over  a  mandril  25  mm.  in  diameter,  by  means  of  a  slowly  working 
mechanical  contrivance. 

G.  WROUGHT  IRON  FOR  BOILER  WORK. 

1.  The  portions  of  boilers  composed  of  wrought  iron  should  be  sub- 
mitted to  the  following  tests: 

(a)  For  plates: 

(1)  Tension  test. 

(2)  Bending  test. 

(3)  Forging  and  punching  test. 
(&)  For  angle  irons: 

(1)  Tension  test. 

(2)  Bending  test. 

(3)  Forging  and  punching  test. 
(c)  For  rivet  iron : 

(1)  Tension  test. 

(2)  Forging  and  bending  test. 

2.  The  welding  test  for  angle  iron  is  not  absolutely  necessary,  but  it 
is  desirable. 

3.  Hot  shortness  (rupture  while  hot),  which  would  be  shown  by  it, 
is  also  demonstrated  by  the  hot  bending  test. 

H.  Low  OR  MILD  STEEL  FOR  BOILER  WORK. 

Wherever  bars  and  plates  of  mild  steel  (Bessemer,  Martin,  or  Thomas) 
take  the  place  of  wrought  iron  in  the  construction  of  boilers  they 
should  be  submitted  to  the  following  tests : 

1.  Tension  tests. 

2.  Gold  and  red-hot  bending  tests.     The  edges  of  test  pieces  should 
be  chamfered ;  if  plates  are  more  than  6  mm.  thick,  the  bending  should 
be  done  around  a  mandrel  25  mm.  in  diameter,  by  means  of  a  slowly 
working  mechanical  contrivance,  and  up  to  the  limit  of  a  given  angle. 


19 

This  test  furnishes  ail  example  of  how  the  material  will  behave  when  Avorked 
into  a  boiler.  A  mandrel  25  mm.  in  diameter  is  handy,  and  conforms  to  the  direction 
most  commonly  followed  at  present. 

3.  Beudiiig  tests  after  tempering.     The  test  pieces,  which  are  cham- 
feied  along  their  edges,  should  be  heated  uniformly  throughout  their 
entire  length  to  a  cherry  red  (550°  to  650°  C.),  then  quenched  in  water 
of  about  25°  C.,  and  then  bent  according  to  the  instructions  given 
under  2,  above. 

Experience  has  shown  that  there  should  be  employed  for  boilers  onry  such  mild 
steel  as  is  but  little  hardened  by  quenching  and  readily  worked  after  it.  Mild 
steel,  having  a  resistance  of  from  38  to  42  kilograms  per  square  millimeter,  and  20 
per  cent  elongation,  generally  fulfills  this  condition,  but  it  is,  however,  prudent  to 
submit  it  to  the  above  bending  tests  after  having  tempered  it. 

4.  Forging  tests — that  is  to  say,  flattening  out  while  red  hot.     The 
test  for  punching  is  useless,  because  the  punching  of  holes  in  plates  of 
mild  steel  should  be  avoided,  on  account  of  the  resulting  fissures. 

5.  It  is  recommended  that  those  establishments  which  employ  mild 
steel  in  practice  should  make  also  tests  for  its  welding  properties. 

Against  the  general  introduction  of  the  welding  test  there  may  be  urged  above  all 
its  difficulty,  the  dependence  of  its  success  upon  the  skill  and  experience  of  the 
workmen,  and  finally  the  fact  that,  while  rnild  steel  can  be  welded,  riveting  is  safer. 
It  is  true  that  corrugated  and  rolled  plates  of  the  Fox  patent,  fire  tubes  and  gas 
tubes  of  mild  steel,  are  welded,  but  all  of  those  pieces  are  tested  individually  (multi- 
ple test).  Again,  weldable  mild  steel  either  can  not  be  tempered  at  all,  or  at  least 
not  readily  tempered,  and  is  less  sensitive  to  temperature,  but  all  of  this  is  deter- 
mined already  by  the  bending  test  when  tempered. 

Tests  of  plates  of  annealed  mild  steel  are  unnecessary.  The  following  are  the 
reasons  against  such  tests :  On  account  of  the  cost,  plate  iron  is  not  always  annealed. 
Only  in  the  case  of  small  diameters  is  rolling  done  Avhilo  hot.  In  hand  Hanging  the 
plates  are  heated  only  locally.  Pitted  heads  are  no  longer  annealed,  because  annealing 
distorts  them.  The  presence  of  strains  in  the  metal  can  not  be  determined  by  that  test. 

During  the  process  of  annealing  it  is  not  only  difficult  to  determine  the  tempera- 
ture, which  is  of  so  much  importance,  but  also  the  time  of  its  action.  Measure- 
ments of  temperature  would  complicate  tests  A^ery  much.  Finally,  the  real  issue 
always  is  to  determine  the  nature  of  the  material  in  the  condition  that  it  is  delivered. 

In  favor  of  tests  after  annealing,  there  may  he  mentioned,  firstly,  on  account  of 
interior  strains  which  exist  in  plates  of  mild  steel,  comparative  results  can  be  obtained 
only  when  they  are  annealed ;  secondly,  the .  same  material  when  rolled  into  plates 
of  different  thicknesses  gives  different  results,  and,  finally,  comparative  tests  made 
of  annealed  plates  and  of  plates  not  annealed  permit  a  study  to  be  made  of  the 
defects  that  result  from  a  lack  of  care  in  their  manufacture. 

The  following  should  be  observed  in  regard  to 

THE  PLACE  AT  WHICH  AND  THE  MANNEK  IN  WHICH  TEST 
PIECES  SHOULD  BE  CUT  OUT  OF  BOILEE  PLATES, 

notably  in  the  case  of  plates  that  have  already  seen  service : 

A.    PLANE    PLATES,    NOT   WORKED. 

In  the  case  of  plates  with  trimmed  edges  test  strips  for  longitudinal  and 
trans  verse  bars  will  be  taken  from  the  edges,and  in  the  case  of  untrimmed 
plates  at  least  30  mm.  inside  of  the  edges.  The  cutting  of  the  strips  may 


20 

be  done  either  by  means  of  shears  or  by  sawing.  Test  strips  cut  from 
bridge  plates  by  means  of  shears  must  be  straightened  out  cold  under 
pressure,  or  with  wooden,  copper,  or  leaden  hammers;  before  dressing 
them  for  tensile  tests  5  mm.  must  be  planed  off  on  each  side  to  remove 
the  traces  of  the  shear  cut;  test  strips  cut  from  boiler  plates  by  means 
of  shears  will  be  treated  in  the  same  way.  They  will  be  annealed  only 
when  especially  desired. 

U.      PLATES   WORKED   ENTIRELY   OR   PARTIALLY,    AND   PLATES   THAT   HAVE    BEEN 

ALREADY  IN   USE. 

(1)  When  the  properties  of  the  plate,  before  it  was  worked,  are  to  be  determined. 

In  this  case,  pieces  out  of  which  the  test  strips  are  to  be  cut  should 
be  taken  from  the  parts  having  uniform  thickness  and,  as  far  as  pos- 
sible, plane  surfaces. 

If  only  a  curved  piece  of  plate  can  be  obtained,  then  this  will  be 
prepared  by  drilling  and  chiselling,  or  by  means  of  the  circular  saw; 
the  test  strips  will  be  cut  out  of  this  piece  in  the  same  manner.  From 
plane  pieces  of  plate,  the  test  strips  may  be  cut  by  means  of  shears,  and 
will  then  be  treated  as  described  above. 

The  curved  test  strips  will  be  cautiously  straightened  under  pressure, 
or  with  wooden,  copper,  or  leaden  hammers,  or  with  iron  hammers  by 
interposing  pieces  of  wood. 

(2)  When  the  mechanical  properties  of  the  plate,  after  having  been  worked,  are 
to  be  determined. 

In  this  case  it  is  impossible  to  give  general  rules  either  for  the  place 
from  which  or  for  the  manner  in  which  the  test  strips  are  to  be  cut. 
The  principles  according  to  which  test  pieces  are  cut  out  in  the  above- 
described  cases  will  be  considered  as  much  as  practicable. 

J.  WIRE. 
Wire  should  be  subjected — 

1.  To  the  tensile  test. 

2.  To  the  torsion  test,  by  means  of  machines  excluding  arbitrary 
working. 

3.  To  the  bending  test,  by  repeated  bending  to  and  fro  with  machinery 
around  a  mandrel  of  5  mm.  diameter. 

The  use  of  a  mandrel  with  a  given  diameter  suppresses  the  bad  method  of  clamping 
wire  and  bending  it  to  and  fro  in  a  vise  with  sharp  edged  jaws. 

The  permanent  committee  has  been  requested  to  submit  a  report  at  the 
next  convention  on  a  new  apparatus  used  in  America  for  testing  wire  and 
described  by  Mr.  Henning,  of  New  York,  at  tJtc  conference  of  Vienna. 

K.  WIRE  EOPE. 

Wire  rope  should  be  tested — 

1.  By  tension. 

2.  By  shock  or  impact,  longitudinally. 


21 

The  bending  test  is  valuable  only  when  it  is  of  long  duration,  but  that  is  difficult 
to  obtain  in  practice,  and  is,  moreover,  snperiluons,  since  each  wire  in  the  rope  has 
already  been  tested  by  bending. 

L.  MEASUREMENTS  TO  BE  MADE  DURING  TENSION  TESTS. 

1.  During  tension  tests  there  should  be  measured — 
(a)  The  tensile  strength. 

(/>)  The  reduction  of  cross  section  at  the  point  of  rupture. 

(c)  The  elongation  after  rupture  (see  M,  No.  1). 

(d)  The  limit  of  elasticity  or  of  proportional  elongation. 

2.  It  is  recommended  that  there  should  be  obtained  as  many  individ- 
ual results  as  possible  for  the  construction  of  the  work  diagram,  unless 
the  same  is  traced  by  special  apparatus. 

3.  In  obtaining  the  diagram,  special  importance  must  be  attached  to 
the  determination  of  the  velocity  with  which  it  was  traced. 

4.  In  obtaining  work  diagrams  the  five  following  points  should  be 
determined  as  exactly  as  possible : 

(a)  Limit  of  proportional  elongation,  or  of  elasticity. 

(b)  Yield  point. 

(c)  Commencement  of  contraction. 

(d)  Maximum  load  (fall  of  lever). 

(e)  Limit  of  rupture. 

5.  The  area  of  the  diagram  must  be  calculated  up  to  the  limit  of 
rupture. 

Practically,  only  that  work  is  of  importance  which  is  done  by  the  entire  bar  up 
to  the  beginning  of  contraction.  From  that  instant  the  principal  work  is  done  by 
the  contracting  portion  only ;  but  in  the  case  of  most  materials  of  construction  such 
work  is  inconsiderable,  so  that  no  appreciable  error  is  caused  by  determining  the 
area  of  diagram  to  the  point  of  rupture.  It  appears,  therefore,  advisable  to  continue 
this  for  the  present,  all  the  more  as  it  is  difficult  to  determine  the  moment  of  maxi- 
mum load.  Besides,  it  is  desirable  to  take  account  of  the  portion  of  the  diagram 
corresponding  to  the  event  of  contraction,  because  there  may  be  relations  between 
the  local  elongation  produced  after  the  commencement  of  contraction  and  the  work 
required  for  it. 

M.  FORM  OF  TEST  PIECES  FOR  TENSION  TESTS. 

1.  Round  bars  for  tests  will  be  made  in  four  types,  viz,  with  diame- 
ters respectively  of  10,  15,  20,  and  23  mm.,  according  to  the  require- 
ments and  possibilities.  The  length  of  the  cylindrical  part,  the 
so  called  "actual  length,"  should  at  each  end  exceed  by  at  least  10  mm. 
the  "test  length,"  viz,  the  length  on  which  the  elongation  is  to  be 
measured.  In  order  that  the  percentage  of  elongation  may  be  inde- 
pendent of  the  form  and  dimensions  of  the  cross  section,  the  test  length, 
?,  should  be  made  proportional  to  the  square  root  of  the  cross-sectional 
area,  /.  On  the  basis  of  the  internationally  adopted  bar  of  20  mm. 
diameter,  200  mm.  test,  and  220  mm.  actual  length,  this  renders — 

I  =  11.3  Vf~ 


22 

The  elongation  should  be  measured  on  two  diametrically  opposite 
sides  of  the  bar,  on  each  of  the  broken  sections  from  the  initial  points 
of  the  test  length  to  the  point  of  rupture  and  the  mean  taken  of  each 
pair  of  measurements. 

When  rupture  takes  place  outside  the  middle  third  of  the  test  length, 
that  test  should  be  rejected,  or  a  process  like  the  following  must  be 
applied,  which,  however,  presupposes  that  there  is  marked  on  the  bar 
not  only  its  actual  and  its  test  length,  but  also  a  graduation  to  centi- 
meters : 

Let  us  suppose  that  in  the  case  of  the  bar  shown  in  fig.  2  the  rupture 
occurs  between  the  fourth  and  the  fifth  graduation  lines;  then  starting 
from  the  point  of  rupture,  the  graduation  lines  are  marked  as  shown  in 
the  figure.  To  the  left  we  now  measure  from  1  to  5  or  from  1  to  10,  accord- 
ing to  whether  the  elongation  of  10  cm.  or  of  20  cm.  is  to  be  determined; 
in  each  case  the  length  0-b  and  b-1  must  also  be  measured.  To  the 
right  we  can  only  measure  from  0  to  3,  and  to  this  has  to  be  added  the 
piece  corresponding  to  the  missing  one  on  the  left  side — that  is,  3-5  if 
the  elongation  of  10  cm.,  and  3-10  if  the  elongation  of  20  cm.  is  to  be 


IS   14  13  12  II   10   9    8    7    6    S   4    3    2    I 


19   IB  17  16  15  14   13  12   II    10   9     6     7     65     432     I 


FlO.   2. 

determined.  In  this  way  the  measurement  of  the  bar  is  accomplished 
very  nearly  as  if  the  rupture  had  taken  place  in  the  middle  of  the 
specimen.  The  above-mentioned  graduation  and  the  method  of  meas- 
urement herein  described  must  both  be  made  on  the  two  opposite  sides 
of  the  bar. 

2.  The  actual  and  the  test  length  of  bars  with  rectangular  section 
depends  on  the  area  of  the  transverse  section  and  should  be  computed, 
as  in  the  case  of  round  bars,  according  to  the  formula: 

Test  length=Z=11.3  Vf 

Likewise,  the  graduation  of  the  bars  and  the  method  of  measuring  the 
elongation  after  rupture  is  the  same  here  as  in  the  case  of  round  bars. 
It  is  recommended  that  the  elongation  of  bars  with  rectangular  section 
should  be  measured  on  the  two  narrow  sides  as  well  as  on  one  of  the 
wide  sides,  and  that  there  should  be  given  separately  the  mean  of  the 
first  two  measurements  and  the  result  of  the  last- mentioned  one. 

3.  If  the  width  and  thickness  of  the  test  pieces  with  rectangular  sec- 
tion can  be  chosen  at  will,  there  should  be  given  for  the  width  30  mm. 
and  for  the  thickness  10  mm.,  and  we  should  consider  in  general  a  sec- 
tion of  30  bv  10  mm.  as  normal. 


23 


In  the  place  of  the  old  width  of  bars  of  50  mm.  the  width  of  30  mm.  will  be  exclu- 
sively adopted,  principally  011  account  of  the  small  testing  machines  used  in  smelt- 
ing works,  the  power  of  which  in  most  cases  does  not  exceed  50  tons. 

4.  When  thickness  of  material  is  given,  as  in  the  case  of  plates,  then 
for  a  thickness  not  exceeding  24  mm.  there  will  be  adopted  for  the  test 
pieces  a  width  of  30  mm.     From  25  mm.  upward  in  thickness,  thickness 
will  be  taken  as  width,  and  there  will  be  given  to  the  test  piece  a  thick- 
ness of  10  mm. 

In  order  not  to  lose  in  the  last-named  case  the  skin  of  the  metal, 
additional  thickness  will  be  given  at  the  ends  for  the  formation  of  the 
bar  heads  for  mounting. 

When  the  machines  are  not  powerful  enough,  the  above  limits  of  24 
and  25  mm.  may  be  replaced  in  exceptional  cases  by  the  limits  of  16  and 
17  mm. 

5.  In  flat  iron,  angle  iron,  T  iron,  channel  iron,  I  beams,  etc.,  test 
pieces  of  30  mm.  in  width  as  the  maximum  will  be  cut  in  the  direction 
of  the  length.     In  the  case  of  great  width  of  the  flat  iron,  or  of  the 


100 — »t 


FIG.  3. 


legs  of  the  angle  iron,  or  of  the  flanges  and  webs  of  I  beams  and  chan- 
nel irons,  test  bars  will  be  cut  out  in  successive  lengths,  as  shown  in 
fig.  3,  so  that  the  entire  cross  section  may  be  considered  in  the  test. 

G.  The  skin  of  the  metal  resulting  from  rolling  must  invariably  be 
preserved  on  the  test  pieces. 

M".  BENDma  TESTS. 

1.  The  slow- working  mechanical  contrivance  by  means  of  which  bend- 
ing tests  will  be  made  (see  above,  under  Heading  E)  should  fulfill  the 
following  conditions: 

It  may  either  act  by  central  pressure  between  two  supports  or  by 
lateral  pressure  on  one  of  the  ends  of  the  specimen,  the  other  being 
held  by  the  clamp.  The  apparatus  should  be  simple  and  capable  of 
working  rapidly.  The  part  w,here  the  most  strain  takes  place  in  the 
test  specimen  should  be  clearly  visible.  The  bending  should  take 
place  in  a  continuous  way,  and  when  it  is  done  around  a  mandrel  the 
diameter  of  such  mandrel  should  be  as  small  as  possible. 

The  test  piece  should  have  a  rectangular  section,  the  width  of  which 
should  be  to  the  thickness  as  3  to  1.  The  edges  should  be  slightly 


24 

rounded  off.  For  rivet  iron  and  square  iron  the  cross  section  will 
remain  unchanged. 

The  red-hot  test  should  be  made  as  quickly  as  possible.  In  cold- 
bending  tests  the  rapidity  is  not  important. 

The  angle  of  bending  is  not  in  itself  sufficient  to  determine  the  defor- 
mation of  the  test  piece.  One  must  also  take  into  account  the  radius 
of  curvature  on  the  convex  side,  which  may  be  determined  either  directly 
by  means  of  templets  or  indirectly  by  measuring  the  elongation  on  the 
tension  face. 

The  permanent  committee  has  been  requested  to  devise  the  most  suitable 
and  simple  method  of  measurement.  It  has  also  been  requested  to  study 
the  question  of  bending  tests  with  injured  specimens. 

The  permanent  committee  has,  besides,  been  instructed  to  make  an  inves- 
tigation into  the  causes  of  irregularities  in  the  behavior  of  mild  steel, 
which  often  manifest  themselves  by  unforeseen  ruptures,  etc.,  although 
samples  taken  from  the  ends  of  ruptured  bars,  on  being  subjected  to  an 
examination  of  quality,  are  found  to  be  perfectly  normal.  Administration 
authorities,  etc.,  are  requested,  when  a  case  presents  itself,  to  place  the 
material  at  the  disposal  of  the  committee,  in  order  that,  together  with  an 
exhaustive  examination,  its  chemical  composition  may  also  be  considered. 

III.  TESTS  OF  OAST  IEOK 

1.  Test  pieces  of  cast  iron  should  have  the  form  of  prismatic  bars  of 
110  cm.  actual  and  100  cm.  test  length  and  a  cross  section  3  cm.  square. 
They  should  be  provided  with  an  extension  25  by  25  mm.  in  cross  sec- 
tion, from  which  there  can  be  cut,  if  it  is  deemed  necessary,  cubes  25 
mm.  high  for  compression  tests. 

Greater  dimensions  would  be  preferable  for  transverse  as  well  as  for  tension  tests, 
but  for  the  sake  of  conforming  to  Wacliler's  fundamental  experiments  the  dimen- 
sions adopted  by  him  have  been  retained. 

2.  The  test  pieces  should  be  cast  in  a  mold  inclined  10  cm.  per  meter. 

Wachlers  test  bars  were  cast  vertical  (it  is  not  stated  whether  from  the  top  or 
bottom),  but  it  has  been  noticed  with  some  kinds  of  cast  iron  that  castings  become 
too  cold  when  they  are  cast  from  the  bottom,  and  there  is  lacking  experience  in  cast- 
ing them  from  the  top.  The  manner  of  casting  also  depends  on  the  nature  of  the 
cast  iron,  on  the  skill  of  the  molders,  foundry  men,  etc. 

3.  The  height  of  pressure,  measured  by  the  height  of  the  runner 
stick,  will  be  20  cm. 

4.  Casting  is  done  in  dry  sand  molds. 

5.  There  will  be  determined  by  the  test — 

(a)  The  resistance  to  flexure  up  to  the  point  of  rupture  and  the  cor- 
responding work  on  three  pieces. 

(b)  The  tensile  strength  of  round  bars  20  mm.  in  diameter  and  200 
mm.  in  test  length,  made  out  of  the  broken  parts  obtained  from  the 
test  under  a,  two  to  be  made  out  of  each  of  the  three  bars  tested  there. 

(c)  The  compressive  strength  of  cubes  3  cm.  (2.5  cm.)  length  of  edge, 
also  made  out  of  the  broken  parts  obtained  from  the  test  under  a,  two 


25 

to  be  made  and  tested  out  of  each  of  the  three  bars  tested  there.  The 
pressure  will  be  applied  in  the  direction  of  the  length  of  the  original 
test  piece. 

G.  The  faces  of  the  test  pieces  for  flexure  and  for  compression  will 
retain  the  skin,  as  coming  from  the  mold. 

7.  Special  castings,  such  as  supports  of  bridges,  pipe,  etc.,  will  be 
submitted  to  special  tests  conforming  to  the  use  to  which  they  are  to 
be  put. 

IV.  TESTS  OF  COPPER,  BRONZE,  A^D  OTHER  METALS. 

1.  COPPER. 

To  determine  the  quality  of  copper  in  plates,  sheets,  bars,  and  wire, 
the  following  tests  are  deemed  necessary: 

A.  Copper  in  plates,  in  sheets,  and  in  bars: 

(1)  Tension  test. 

(2)  Cold  bending  test. 

(3)  Hot  bending  test. 

B.  Copper  wire : 

(1)  Tension  test. 

(2)  Bending  test. 

(3)  Torsion  or  twisting  test. 

CONDITION   OF   THE   MATERIAL. 

The  tests  will  be  made  in  the  condition  in  which  the  material  is  deliv- 
ered, or,  if  desired,  those  under  A  will  also  be  made  in  its  soft  condition. 
To  determine  the  properties  of  the  material  in  its  natural  state,  it  is 
necessary  to  reduce  the  test  specimen  to  the  soft  condition.  For  this 
purpose  the  test  pieces,  after  having  been  cut  out,  but  before  their  final 
shaping,  will  be  heated  in  the  furnace  at  a  temperature  of  600°  to 
700°  C.,  but  not  beyond  this,  then  cooled  in  the  air  until  they  are  a  dull 
red,  and  finally  plunged  in  water  at  a  temperature  of  15°  C. 

CUTTING   OF   THE    TEST  PIECES. 

The  test  pieces  must  be  cut  out  cold  by  means  of  a  saw,  file,  or 
machine  tool,  special  care  being  taken  that  no  subsequent  straighten- 
ing is  required.  When  it  does  become  necessary,  straightening  must 
be  done  cautiously  and,  as  far  as  possible,  by  means  of  copper  hammers 
or  wooden  mallets.  If  the  test  is  to  be  made  in  the  soft  condition  of 
the  material,  then  the  test  pieces,  as  cut  out  roughly,  may  be  heated 
for  the  purpose  of  straightening.  In  this  case,  however,  they  must  be 
heated  once  more  in  order  to  reduce  them  to  the  soft  condition. 

FORM   AND   FINISH   OF   THE   TEST   PIECES. 

The  test  length  I  of  test  bars  will  be  determined,  as  in  the  case  of 
wrought  iron  and  steel  (see  II,  M  1),  according  to  the  formula 

1  =  11.3  VJ, 
wherein  /  is  the  cross- sectional  area  of  the  bar. 


26 

Iii  the  case  of  copper,  the  finishing  of  the  test  pieces  has  an  exceed- 
ingly great  influence  on  the  results  of  tests;  therefore,  the  utmost 
caution  should  be  exercised  in  shaping  test  pieces  into  their  final  form, 
special  care  being  taken  never  to  withdraw  the  cutting  tool  within  the 
limit  of  the  test  length,  and  also  to  cut  only  thin  shavings  toward  the 
end.  The  test  pieces  will  be  dressed  in  the  direction  of  their  length 
and  polished  with  emery.  The  sharp  edges  of  the  test  pieces  used  for 
transverse  tests  will  be  rounded  with  a  file. 

It  is  recommended  also  to  give  a  round  of  1  mm.  radius  to  the  edges 
of  the  flat  bars  used  for  tension  tests. 

EXECUTION   OF   TESTS. 

Tension  tests,  and  the  measuring  of  elongation,  will  be  done  as  in 
the  case  of  iron  and  steel. 

The  cold  bending  test  should  be  made  over  a  mandrel  with  a  diameter 
equal  to  the  thickness  of  the  plate,  of  the  sheet,  of  the  bar,  or  of  the 
wire.  It  must  not  be  made  at  a  temperature  below  10°  0.  In  the  case 
of  plates,  sheets,  and  bars,  those  specimens  that  stood  bending  around 
a  mandrel  up  to  180°  are  then  pressed  together  until  the  inner  faces 
come  into  close  contact.  The  bending  tests  of  wire  will  conform  to 
those  prescribed  for  steel  and  iron  wire. 

The  hot  bending  test  will  be  made  on  bars  brought  to  a  cherry  red 
in  a  furnace.  Those  pieces  will  be  bent  until  rents  are  produced  or 
until  the  interior  faces  touch.  Torsion  tests  of  wire  will  conform  to 
those  prescribed  for  iron  and  steel  wire. 

2.  METALS  AND  ALLOYS. 

To  determine  the  quality  of  the  metals  and  alloys  employed  in  the 
construction  of  machines  and  railroads,  in  architecture,  and  shipbuild- 
ing, the  following  tests  should  be  made: 

1.  Tension  tests. 

2.  Compression  tests. 

3.  Transverse  tests. 

4.  Hot  and  cold  bending  tests. 

The  tests  will  conform  to  those  prescribed  for  cast  iron  or  those  pre- 
scribed for  copper  according  to  the  properties  of  the  material  to  be 
tested.  In  the  first  case,  tests  1  to  3  are  recommended;  in  the  second 
case,  tests  2  to  4. 

The  permanent  committee  was  directed  to  investigate  the  upsetting  test 
and  to  suggest  rules  for  it,  not  only  in  the  case  of  copper ,  brass,  and  other 
metals,  but  also  in  the  case  of  iron  and  steel. 

V.   TESTS  OF  WOOD. 

1.  In  order  to  judge  technically  of  the  qualities  of  wood,  as  much  as 
possible  of  the  following  information  should  be  procured :  Statement  of 
the  place  of  growth,  whether  the  tree  stood  isolated  or  in  a  crowded 


27 

forest,  and  from  what  part  of  the  tree  the  test  piece  was  taken.  Finally, 
a  statement  of  the  age  and  the  time  of  cutting. 

2.  On  account  of  the  great  difference  existing  between  individuals 
and  between  the  different  parts  of  the  same  tree,  three  samples  at  least 
are  necessary  to  render  an  opinion. 

;>.  The  outward  appearance  of  each  sample  should  be  described  as 
follows: 

A.  For  the  longitudinal  section,  or,  better  still,  for  surface  of  natural 
split,  state — 

(<()  Whether  the  fibers  run  straight  or  not. 

(b)  Whether  there  are  knots ;  if  so,  their  nature. 

B.  For  the  transverse  section — 

(c)  In  the  case  of  ring-porous  leaf  trees  and  for  all  members  of  the 
pine  family  state — 

(«-)  The  mean  width  of  the  annual  layers  in  millimeters. 
(ft)  The  increase  or  decrease  of  width  of  annual  rings  in  a  radial 
direction. 
(;/)  The  form  of  annual  rings,  whether  circular  or  eccentric. 

(d)  For  trees  with  needle  shaped  leaves  the  approximate  relation 
between  the  part  of  the  tree  coming  from  the  spring  growth  and  the 
part  coming  from  the  autumn  growth,  as  apparent  from  the  average  of 
annual  layers. 

4.  There  will  be  given  for  each  specimen  the  specific  weight  not  only 
in  the  accidental  condition  of  moisture  existing  during  the  test,  but 
also  when  air-dried — that  is,  after  having  been  dried  at  a  temperature 
of  101°  to  105°  0.     There  will  likewise  be  determined  the  percentage 
of  moisture  of  each  sample  at  the  time  of  test,  as  compared  with  the 
state  of  air- dry  ness.     (See  above.) 

5.  The  pressure  test  and  the  transverse  test  serve  as  a  criterion  of 
the  strength  and  the  quality  of  the  wood. 

(a)  The  test  of  compression  should  be  made  on  prisms  15  cm.  long 
and  with  a  cross-section  10  cm.  square,  the  test  pieces  to  be  mounted 
centrally,  the  two  end  surfaces  exposed  to  pressure  being  parallel. 

(b)  The  transverse  test  will  be  made  on  prismatic  bars  100  cm.  long, 
with  a  square  section  of  10  cm.  by  10  cm.  and  a  clear  length  of  150  cm. 
between  the  points  of  support.     In  order  not  to  injure  the  test  piece 
while  making  the  test,  there  will  be  placed  on  it,  at  the  point  at  which 
the  load  is  applied,  a  rider  2  cm.  thick  and  20  cm.  long,  and  it  will  be 
protected  by  still  other  means  if  deemed  necessary.    The  flexure  will 
be  pushed  to  rupture.    The  rupture  of  a  few  fibers  or  splinters  will 
not  be  considered  as  rupture  of  the  piece. 

(c)  The  strain  at  the  moment  of  rupture  should  be  calculated  by 
means  of  the  formula  used  for  flexure,  the  supposition  being  that  it 
holds  good  up  to  rupture. 

(d)  The  quality  is  determined  by  the  work  corresponding  to  the  flex- 
ure of  the  specimen  of  the  dimensions  before  given,  the  work  being 


28 

rated  by  a  flexure  diagram  pushed  or  carried  to  the  maximum  value  of 
the  effort  of  Hexure. 

G.  In  order  to  obtain  a  correct  mean  for  an  entire  trunk,  the  various 
layers  of  which  are  different  in  character,  there  should  be  taken  for  the 
pressure  test  as  well  as  for  the  transverse  test  at  least  two  specimens 
from  the  heart  and  two  specimens  from  the  outer  part  of  the  tree,  the 
outer  edges  of  the  latter  two  being  situated  in  the  circumference  of 
the  trunk. 

7.  The  report  of  transverse  tests  should  be  completed  by  sketches 
indicating  for  each  test  piece  the  position  of  the  annual  layers  with 
reference  to  the  direction  of  the  force  acting  on  the  piece.  Sap  wood 
will  be  bent  in  the  direction  of  the  radius,  from  the  center  toward  the 
outside. 

YI.  TESTS  OF  SHIPBUILDING  MATERIAL. 

1.  Shipbuilding  materials  of  wrought  iron,  such  as  plates,  angle,  bar, 
shape,  and  rivet  iron,  should  be  submitted  to  the  following  tests: 

(a)  Tension  test. 

(b)  Cold  bending  test. 

(c)  Red-hot  bending  test  or  forging  test. 

2.  Shipbuilding  materials  of  mild  steel,  such  as  plates,  angle,  bar, 
shape,  and  rivet  iron, 'should  be  submitted  to  the  following  tests: 

(a)  Tension  test. 

(6)  Cold  bending  test. 

(c)  Red-hot  bending  test  or  forging  test. 

(d)  Tempering  test  and  bending  after  tempering. 

(e)  It  is  recommended  that  those  who  employ  mild  steel  in  practice 
should  examine  it  witli  regard  to  its  welding  properties. 

Tension  tests  should  be  made  on  bars  of  standard  dimensions  cut 
from  the  material  just  as  it  is  delivered.  The  strips  for  bending  tests 
will  be  prepared  in  precisely  the  same  way  as  described  for  testing  of 
boiler  plates  (see  above  under  II,  G-  and  H).  The  tempering  test  and 
bending  test  after  tempering  will  be  made  as  in  the  case  of  boiler 
plates,  with  this  exception:  The  bending  of  the  strips  by  a  slow- 
working  mechanical  contrivance  will  be  done  around  an  inner  radius, 
the  size  of  which  depends  on  the  thickness  of  the  plate. 

VII.  TESTS  OF  STONE. 
A.  STONE  IN  GENERAL. 

Stone  will  be  tested  according  to  uniform  principles  from  the  point 
of  view  of  its  resistance  to  boring  and  to  quarrying. 
1.  Methods  of  testing: 
The  tests  of  resistance  to  boring  will  be  made — 

(a)  Either  by  means  of.  a  jumper  drill,  or, 

(b)  l>y  means  of  a  rotary  boring  machine. 

If  the  former  is  to  be  employed,  it  is  recommended  to  take  the  one 
used  by  the  Saxon  mining  engineer  Hausse,  in  Zankerrode,  for  testing 
the  resistance  of  stone  to  boring.  It  is  described  in  the  ki  Deutsche 


29 

Berg-  und  Hiittenmaimische  Zeituug,"  1882,  Nos.  33  and  34.  With  this 
machine  or  some  similar  one,  or  by  means  of  a  rotary  boring  machine, 
the  work  required  for  the  drilling  of  a  hole  of  given  dimensions  is 
determined  in  meter-kilograms. 

2.  Determination  of  the  most  favorable  conditions  for  work  before 
undertaking  resistance  tests: 

In  the  case  of  any  given  kind  of  stone,  the  minimum  amount  of  work 
required  for  a  drill  hole  of  given  diameter  is  largely  influenced  by— 

(d)  The  moment  of  drop  of  the  drill,  or,  in  the  case  of  the  rotary  bor- 
ing machine,  the  amount  of  vertical  pressure  acting  on  the  boring 
tool,  and  its  rotating  velocity;  again, 

(b)  The  shape  and  cutting  angle  of  the  drill  or  of  the  teeth  of  the 
borer,  and 

(c)  The  number  of  blows  for  one  revolution  of  the  drill  when  drilling 
by  impact. 

Preliminary  tests  are  therefore  recommended  for  determining  the 
most  suitable  combinations.  As  a  basis  of  those  preliminary  tests  it 
may  be  assumed  that  for  a  hole  25  mm.  in  diameter  bored  by  impact 
the  most  favorable  moment  of  drop  is  comprised  between  G  and  9 
meter-kilograms,  and  that  for  the  rotary  boring  machine  the  pressure 
should  probably  vary  between  30  and  130  atmospheres;  also,  that  in 
boring  by  impact  the  cutting  angle  should  vary  between  70°  and  110° 
and  the  drill  should  be  turned  from  one-thirtieth  to  one- sixth  of  the 
entire  circumference  at  each  blow;  finally,  that  for  the  rotary  boring 
machines  at  present  in  use  the  most  favorable  diameter  of  bore  proba- 
bly varies  between  40  and  80  mm. 

3.  Special  uniform  directions : 

After  the  most  suitable  methods  of  test  of  a  given  kind  of  stone  have 
been  determined  by  means  of  the  above  preliminary  tests,  then  the 
diameter  of  drill  hqle  for  drilling  by  impact  shall  be  fixed  at  25  mm., 
corresponding  to  the  mean  diameter  of  the  one-man  drill  hole.  In  order, 
however,  to  determine  whether  the  amount  of  work  required  per  unit 
of  drill-hole  space  is  dependent  on  the  diameter  of  the  hole,  there  shall 
also  be  employed  larger  diameters.  It  is  recommended  to  use  as  such 
35,  45,  and  G5  mm.,  corresponding  to  the  mean  diameters  of  the  two- 
man,  three-man,  and  machine  drill  holes.  After  having  determined 
empirically  the  most  favorable  moment  of  drop  for  a  hole  of  25  mm., 
there  will  be  applied  the  law  of  proportional  resistance  to  find  those 
which  correspond  to  the  above  greater  diameters  of  drill  holes. 

For  rotary  borings  no  uniform  diameter  can  be  recommended  for  the 
holes  on  account  of  the  varieties  of  the  existing  boring  machines. 
However,  it  should  be  sought  to  approach  as  near  as  possible  the 
diameters  of  45  and  05  mm.,  recommended  for  drilling  by  impact. 

4.  Other  tests: 

For  the  purposes  of  information,  it  is  desirable  that  the  rocks  sub- 
jected to  the  test  of  resistance  to  boring  should  also  be  submitted  to 
tests  of  compression,  elasticity,  and  shearing. 


30 

5.  Table  of  borings: 

The  following  form  should  be  employed  uniformly  to  record  the  results 
of  the  tests : 

STANDARD  RECORD  BLANK  FOR  BORING. 

1.  Description  of  rock  from  a  geological  and  mineralogical  point 

of  view. 

2.  Miner's  classification  (bard,  very  hard,  extremely  hard). 

3.  Texture  (for  instance,  coarse  grained,  fine  grained,  layers  par- 

allel, perpendicular,  or  oblique  to  axis  of  hole  bored). 

4.  Specific  gravity  of  rock. 

5.  .Diameter  of  drill  hole  when  drilling  by  impact. 

C.  The  diameter  of  hole  and  core  in  the  case  of  a  rotary  boring 
machine. 

7.  Straight  or  curved  edge  drills  in  drilling  by  impact. 

8.  Cutting  angle  when  drilling  by  impact. 

9.  Number  of  blows  in  one  revolution  of  drill  when  drilling  by 

impact. 

10.  Falling  weight  when  drilling  by  impact. 

11.  Mean  height  of  drop  when  drilling  by  impact. 

12.  Number  of  blows  that  were  inquired  to  obtain  observed  depth 

of  drill  hole. 

13.  Number  and  form  of  cutting  teeth  in  the  rotary  drill. 

14.  Statement  of  pressure  and  of  velocity  with  which  the  rotary 

machines  were  worked. 

15.  Depth  of  drill  hole. 

10.  Calculated  or  indicated  drill  work  done,  in  meter-kilograms, 
per  cubic  centimeter  of  drill-hole  space.  (In  the  case  of 
rotary  boring  only  the  annular  space  will  be  counted.) 

B.  BUILDING  STONE. 

a.  NATURAL  BUILDING  STONE. 

1.  Besides  the  petrographic  and  geologic  designation  of  the  stone 
there  must  be  named  the  quarry  as  well  as  the  bench  Avhence  the  speci- 
men comes.  There  must  also  be  given  the  date  of  their  quarrying  and 
consequently  of  their  storage  in  the  depot.  In  the  case  of  great  damp- 
ness of  the  quarry,  the  quarrying  should  be  done  in  the  dry  season. 

As  it  is  sometimes  difficult  for  those  who  make  the  tests  to  verify  the 
exactitude  of  the  statements  made  by  the  owners  of  the  samples  in 
regard  to  their  mineralogical  designation,  it  is  recommended  that  this 
test,  unless  expressly  demanded,  be  left  out  entirely  and  a  statement 
to  this  effect  made  in  the  certificate  of  test.  On  the  other  hand,  it  is 
well  to  correct  striking  errors  in  the  designation  of  rocks  by  notifying 
the  interested  parties  in  regard  to  them. 

Likewise  there  may  be  omitted  in  certain  cases  the  verification  of  the 
statements  as  to  the  quarry  and  the  bench  from  which  the  sample  has 


31 

been  taken,  the  certificate  of  test  with  reference  to  these  points  then 
being  worded  about  as  follows:  "Said  to  be  taken  from  -  -  quarry 
and bench." 

2.  It  is  recommended  that  those  who  are  in  charge  of  the  tests  should 
inform  themselves  before  making  them  as  to  the  use  to  which  the  appli- 
cant desires  to  put  the  materials  (building  stone,  freestone,  flagging, 
ballasting,  paving),  and  to  base  tests  on  that  information  and  not  on 
the  wording  of  the  order. 

3.  Stone  to  be  used  for  freestone  for  structures  or  substructures  should 
be  tested  for  compression  in  the  form  of  cubes  with  planed  faces.     These 
cubes  should  be  placed  between  compression  plates  without  any  inter- 
posed material.     One  of  those  plates   should  move  easily  in  every 
direction. 

According  to  the  use  to  which  the  material  will  be  put,  the  resistance 
to  compression  will  be  tested  normally  or  parallel  to  the  bed,  or  in  both 
directions.  Tests  will  be  made  on  at  least  three  samples  for  each 
direction. 

The  samples  should  be  made  as  large  as  the  strength  of  the  material 
and  the  maximum  power  of  the  testing  engine  may  permit,  10  cm.  length 
of  edges  being,  however,  sufficient  for  stones  of  inferior  strength. 

4.  There  should  be  measured  during  the  tests,  if  possible  at  regular 
intervals  of  pressure,  the  corresponding  loss  of  height  of  the  test 
pieces,  in  order  to  be  able  to  draw  the  diagram  of  work.     There  will  be 
made  also  in  a  similar  way  tension  and  transverse  tests. 

5.  Before  use,  the  test  pieces  should  be  dried  in  a  temperature  of  30° 
G.  until  their  weight  is  constant. 

G.  There  will  be  determined  always  the  specific  gravity  (weight  of 
unit  of  volume),  and  that  after  drying  at  30°  C. 

7.  The  test  of  frost  resistance  will  be  made  on  specimens  of  uniform 
dimensions,  as  the  absorption  of  water  and  the  action  of  frost  depend 
upon  the  extent  of  the  surface.     In  view  of  the  dimensions  of  cement 
test  pieces,  a  cube  7  cm.  in  length  of  edge  is  selected  here.     Only  iu 
the  case  of  very  hard  stone,  smaller  dimensions  may  be  admitted  as  an 
exception;  however,  in  cases  of  this  kind  there  is  very  rarely  any  doubt 
about  the  resistance  of  the  stone  against  frost. 

8.  The  frost  test  comprises : 

(a)  The  determination  of  compressive  strength  in  a  water- saturated 
state  and  its  comparison  with  the  same  strength  when  dry. 

(b)  The  determination  of  the  compressive  strength  of  the  stone  redried 
after  25  successive  freezings  and  thawings,  and  the  comparison  of  that 
strength  with  the  compressive  strength  when  dry. 

(c)  The  determination  of  the  loss  of  weight  resulting  from  25  freezings, 
keeping  account  of  the  fragments  mechanically  separated  by  the  frost 
and  of  the  substances  soluble  in  a  given  quantity  of  water. 

(d)  The  examination  of  the  frozen  stone  by  means  of  a  magnifying 
glass,  especially  to  ascertain  whether  there  are  produced  fissures  or 
splinters. 


32 

0.  For  the  freezing  test  there  will  be  employed: 

For  compression  tests  in  a  dry  state  0  specimens,  3  of  which  are  per- 
pendicular  and  3  parallel  to  the  bed,  unless  indeed  those  tests  have 
already  been  made  (see  above  under  No.  3).  On  account  of  the  law  of 
proportional  resistance,  test  pieces  with  a  greater  length  of  edge  than 
7  cm.  may  be  used. 

For  compression  tests  in  a  water- saturated  state,  but  not  frozen,  6 
specimens,  3  of  which  will  be  crushed  perpendicular  and  3  parallel  to 
the  bed. 

For  freezing  tests,  6  specimens,  3  of  which  will  finally  be  crushed 
parallel  and  3  perpendicular  to  the  bed. 

10.  In  the  execution  of  frost  tests  the  following  details  should  be 
taken  into  account: 

(a)  For  absorption  of  water  the  cubes  will  first  be  immersed  to  a  depth 
of  2  cm.,  and  then  gradually  submerged  completely. 

(b)  There  will  be  used  for  this  immersion  distilled  Avater  at  a  temper- 
ature of  from  15o  to  20°  0. 

(c)  The  test  pieces  saturated  with  water  will  be  exposed  to  a  temper- 
ature of  from  — 10°  to  — 15°  0. 

(d)  The  duration  of  exposure  to  cold  will  be  four  hours  each  time. 
The  test  pieces  will  be  thus  exposed  when  completely  saturated  with 
water. 

(c)  For  thawing  there  will  be  used  a  given  quantity  of  distilled  water 
at  a  temperature  of  from  15°  to  20°  0. 

11.  The  stone  having  been  subjected  to  the  frost  test,  no  additional 
test  of  its  weather- wearing  qualities  is  required;  but  it  is  desirable  to 
carefully  observe  phenomena  of  this  kind  occurring  in  nature,  and  to 
collect  experiences  made  on  material  in  actual  service.     There  should 
be  observed  especially  the  influence  of — 

(a)  The  sun,  with  respect  to  splitting  and  cracking. 

(b)  The  air,  with  respect  to  the  carbonic  acid  it  contains. 

(c)  Kaiii  and  humidity,  with  respect  to  lixiviation  and  decomposing 
stones. 

(d)  Temperature. 

p.  ARTIFICIAL  BUILDING  STONE. 

a  a.   BRICKS. 

1.  For  testing  a  lot  of  bricks,  the  least-burned  ones  should  always 
be  selected. 

2.  The  bricks  will  be  tested  for  compression  in  pieces  of  approxi- 
mately cubical  shape,  obtained  by  superposing  two  half  bricks  and 
binding  them  together  by  a  thin  bed  of  mortar  of  pure  Portland  cement. 
The  pressure  surfaces  will  be  smoothed  by  a  similar  layer  of  the  same 
mortar.     At  least  G  specimens  will  be  tested. 

3.  The  specific  gravity  of  the  bricks  will  also  be  determined. 

4.  To  verify  the  uniformity  of  the  material  the  degree  of  the  porosity 


33 

of  the  bricks  will  be  determined.  For  this  purpose  they  are  first  dried 
and  then  immersed  in  water  until  saturated.  Ten  pieces  are  thus  com- 
pletely dried  on  a  plate  of  iron  and  weighed.  They  are  then  placed  in 
water  for  24  hours,  the  water  not  reaching  above  half  the  thickness  of 
the  bricks  j  after  that  they  are  completely  submerged  for  another  24 
hours;  then,  after  the  surfaces  have  been  wiped,  they  are  weighed 
again.  There  is  thus  obtained  the  mean  quantity  of  water  absorbed. 
The  absorption  should  always  be  calculated  in  volume,  but  there  will 
be  indicated  also  the  per  cent  in  weight  of  water  absorbed. 

5.  The  test  of  frost  resistance  will  be  made  in  the  following  ufanner : 
(a)  Five  of  the  preceding  bricks  saturated  with  water  will  be  tested 

in  that  condition  for  compressive  resistance. 

(6)  The  five  others  will  be  placed  for  4  hours  in  a  refrigerator,  the 
temperature  of  which  is  at  least  — 15°  0.  They  are  then  taken  out  and 
thawed  in  water  at  20°  0.  The  parts  that  spontaneously  break  off 
will  remain  in  the  thawing  vase  until  the  end  of  the  operation.  The 
freezing  is  repeated  25  times.  The  detached  particles  are  dried  and 
weighed,  and  the  weight  obtained  is  compared  with  the  original  weight 
of  the  brick,  which  latter  will  finally  be  examined  under  a  magnifying 
glass  to  ascertain  whether  there  are  any  fissures  or  splinters. 

(c)  After  freezing  the  bricks  a  compression  test  will  be  made.     For 
this  purpose  they  will  be  dried.     The  result  will  be  compared  with  that 
of  the  compression  test  made  on  dried  bricks.     (See  above  under  No.  2.) 

(d)  The  experimental  freezing  of  bricks  does  not  permit  us  to  judge 
absolutely  of  their  resistance  to  freezing.     The  value  of  those  experi- 
ments is  only  relative,  because  they  only  permit  us  to  recognize  the 
bricks  most  destructible  by  frost. 

6.  To  test  bricks  with  regard  to  their  containing  soluble  salts,  five  of 
the  least-burned  ones  of  the  lot  which  have  not  yet  been  in  contact 
with  water  are  selected.    Only  the  interior  is  utilized,  for  which  pur- 
pose the  bricks  are  split  in  three  directions  and  the  interior  edge 
chipped  off  from  each  of  the  eight  pieces  thus  obtained.    These  edges 
are  pulverized  fine  enough  to  pass  through  a  screen  of  900  meshes  per 
square  centimeter ;  then  the  fine  dust  is  removed  by  means  of  a  sieve 
of  4,900 l  meshes  to  the  square  centimeter,  and  the  remaining  materials 
are  used  for  the  test.    Of  this  there  will  be  taken  25  grams,  which  will 
be  mixed  with  250  cubic  cm.  of  distilled  water.     This  will  be  boiled  for 
an  hour,  replacing  from  time  to  time  the  evaporated  water.    Then  it 
will  be  filtered  and  washed.    The  quantity  of  soluble  salts  contained 
in  the  brick  will  then  be  determined  by  evaporating  the  solution  and 
glowing  the  residue.     The  quantity  of  soluble  salts  will  be  indicated  in 
per  cent  of  weight  of  the  brick. 

The  salts  thus  obtained  should  be  submitted  to  a  quantitative 
analysis. 

1  These  are  the  same  sieves  as  those  employed  for  cement  tests.  (See  below  under 
VIII,  C  2.) 

10389 3 


7.  The  tests  as  to  the  contents  of  carbonate  of  lime,  pyrites,  selenite, 
and  other  similar  materials,  should  first  be  made  on  the  uuburnt  clay. 
For  that  purpose  there  will  be  furnished  two  bricks  not  burned.  These 
bricks  will  be  soaked  in  water  and  the  coarse  parts  removed  by  passing 
through  a  screen  of  400  meshes  per  square  centimeter  (about  one-third 
of  a  millimeter  clear  width  of  meshes).  The  sand  thus  obtained  will  be 
'examined  as  to  its  mineralogical  components  by  means  of  a  magnifying 
glass  and  by  treating  it  with  muriatic  acid.  If  impurities  are  found  in 
it,  such  as  carbonate  of  lime,  pyrites,  selenite,  etc.,  samples  of  the  burnt 
bricks— for  instance,  the  remnants  of  the  test  for  soluble  salts — will  be 
tested  in  Papiii's  digester  as  to  the  possible  injurious  influence  of  such 
impurities.  They  will  be  placed  in  Papin's  digester  in  such  a  manner 
as  not  to  come  in  contact  with  the  water,  but  only  with  the  steam ;  the 
pressure  of  that  steam  should  be  one-quarter  of  an  atmosphere  and  the 
test  should  last  three  hours.  There  will  then  be  determined,  by  exami- 
nation with  a  magnifying  glass,  whether  any  splintering  has  taken 
place. 

0  ft  ROOFING  TILES. 

1.  When  roofing  tiles  are  to  be  tested,  the  information  concerning 
them  should  comprise  maximum  and  minimum  dimensions. 

2.  To  determine  its  specific  weight,  the  material  will  be  pulverized, 
that  portion  of  the  powder  being  used  which  has  passed  through  a  sieve 
of  900  meshes  per  square  centimeter  and  has  been  retained  by  a  sieve 
of  4,900  meshes  to  the  square  centimeter.    This  determination  will  be 
made  by  means  of  a  volumenometer. 

3.  The  weight  per  unit  of  volume  of  the  solid  fragment  will  be  deter- 
mined by  the  hydrostatic  method — that  is,  by  measuring  the  volume  of 
water  displaced  by  the  saturated  fragment.    Where  considerable  loss 
is  apt  to  be  caused  through  lixiviation,  the  weight  will  be  determined 
by  means  of  the  volumenometer,  the  test  pieces  being  coated  with 
paraffin. 

4.  Examination  of  the  capacity  for  absorption, 

5.  Determination  of  the  salts  soluble  in  water,  and 

G.  Examination  in  regard  to  injurious  admixtures,  such  as  slakable 
lime,  etc.,  will  be  made  in  a  similar  way  to  the  case  of  tiles  and  bricks. 
(See  above  under  a  a,  Nos.  4, 6,  and  7.) 

7.  Examination  of  the  capacity  for  absorption  of  the  surface  of  the 
tile  and  of  its  permeability  will  be  made  as  follows : 

Fragments  will  be  selected  of  such  dimensions  that  they  can  absorb 
from  20  to  25  cubic  cm.  of  water.  Those  fragments  will  be  dried,  and 
their  edges  will  be  coated  with  wax.  Finally,  there  will  be  affixed  on 
one  of  their  surfaces,  by  means  of  wax,  cylindrical  tubes  of  10  square 
cm.  cross  section. 

The  following  observations  are  then  made: 

(a)  The  'time  necessary  for  the  absorption  of  10  cubic  cm.  of  water 
introduced  into  each  tube  by  means  of  a  little  pipe. 


35 

(&)  The  time  necessary  to  produce  sweat  on  the  lower  surface  of  the 
fragment  after  a  new  introduction  of  10  to  15  cubic  cin.  of  water. 

(c)  The  time  necessary  for  the  formation  of  drops  on  the  lower  face 
after  a  new  introduction  of  10  cubic  cm.  of  water,  and  the  quantity  of 
water  collected  in  case  of  permeability  in  a  vessel  placed  under  the 
fragment. 

8.  To  determine  the  transverse  strength  of  roofing  tiles,  two  bands  of 
Portland  cement,  1  cm.  in  width  and  20  cm.  apart,  will  be  run  across 
the  lower  face.  A  similar  band  will  be  run  across  the  upper  surface 
of  the  tile,  mid  way  between  the  two  lower  ones.  The  latter  will  serve 
as  supports  of  the  tile  during  the  test,  while  the  upper  band  will  receive 
the  load. 

C.  PAVING  AND  BALLAST  MATERIAL,  NATURAL  AND  ARTIFICIAL. 

1.  Information  regarding  the  petrographic  and  geologic  nature  of  the 
material,  its  origin,  etc. 

2.  Information  concerning  the  use  to  which  it  is  to  be  put,  the  same 
as  for  natural  building  stone.    (See  above  under  B,  a.) 

3.  Determination  of  the  specific  weight  of  the  samples. 

4.  All  road-making  materials  that  will  be  exposed  to  frost  when  in 
actual  use  should  be  subjected  to  frost  tests,  according  to  the  rules 
given  for  natural  building  stone.     (See  above  under  B,  a,  Nos.  7  to  10.) 

5.  The  best  test  for  sidewalk  stones  consists  in  determining  their 
resistance  to  wear.    For  this  test  it  is  recommended  to  employ  the 
process  published  by  Professor  Bauschinger  in  No.  XI  of  his*  Mit- 
theilungen. 

For  burnt  stone  the  regularity  of  wear  from  the  outer  skin  toward 
the  interior  should  be  determined  by  repeated  tests  on  the  same  sam- 
ple. Those  tests  must  not  be  confined  to  a  single  sample  of  the  material 
to  be  tested ;  in  fact  it  is  necessary  to  select  for  testing  from  the 
entire  lot  samples  of  the  least,  of  medium,  and  of  the  best  quality  it 
contains. 

6.  The  value  of  paving  materials,  enrockment  or  macadam,  can  be 
determined  conclusively  only  by  the  construction  of  trial  roads,  sub- 
jected to  a  traffic,  in  kind  and  weight  as  uniform  as  possible,  per  meter 
of  width.    It  is  highly  desirable  that  as  many  as  possible  of  such  trial 
roads  should  be  constructed,  all  according  to  a  uniform  plan.    In  refer- 
ence to  this  question,  special  attention  is  invited  to  the  publication  by 
Professor  Dietrich  on  "Materials  of  construction  for  stone  roads." 

7.  In  order  to  determine  the  quality  of  new  paving  materials  more 
rapidly  than  is  possible  by  their  introduction  into  trial  roads,  and  also 
in  order  to  obviate  the  necessity  of  constructing  a  separate  trial  road 
for  each  new  material,  a  more  rapid  process  for  testing  stone  is 
required.    Materials  for  pavement  and  broken-stone  roads  being  sub- 
jected at  once  to  wear  and  to  breakage,  it  is  recommended  to  test  them 
in  revolving  drums  such  as  have  been  used  for  a  long  time  in  France, 


36 

and  are  described  in  the  above-mentioned  publication  of  Professor 
Dietrich;  but  with  a  view  of  augmenting  the  intensity  of  the  shock,  the 
dimensions  of  those  drums  should  be  increased,  giving  them  a  diameter 
of  30  cm.  and  a  height  of  50  cm.  The  velocity  of  rotation  should  also 
be  increased. 

It  should  be  remarked  here  that  the  preparation  of  the  broken -stone 
samples  must  not  be  left  to  the  applicant,  but  for  the  sake  of  uniformity 
should  be  done  by  those  making  the  tests. 

On  account  of  the  perpetually  changing  conditions  of  the  drill  the 
above  test  is  preferable  to  the  drilling  test,  and  pains  should  be  taken 
in  practice  to  compare  its  results  with  the  results  obtained  by  the  con- 
struction of  trial  roads. 

8.  Besides  this  drum  test,  compression  tests  should  also  be  made, 
notably  on  enrockment  materials,  which  are  always  exposed  to  crushing. 
This  test  will  be  made  on  cubical  specimens  having  a  uniform  length  of 
side  of  from  5  to  7  cm. 

9.  Paving  stones  should  be  tested  with  regard  to  the  tendency  to 
wear  smooth. 

10.  For  paving  and  enrockment  materials  it  likewise  appears  neces- 
sary to  select  samples  for  test  from  the  worst,  the  mean,  and  the  best 
of  the  lot,  as  for  those  materials  homogeneousness  of  grain  is  almost 
the  principal  factor. 

11.  Tests  of  asphalt  can  be  made  exhaustively  only  by  the  construc- 
tion of  trial  roads.    To  be  able  to  give  a  suitable  opinion  of  the  results 
of  that  test  it  is  necessary — 

(a)  To  determine  the  quantity  and  the  quality  of  bitumen  contained 
in  the  asphaltum,  whether  natural  or  artificial. 

(6)  To  determine  physically  and  chemically  the  residue. 

(c)  To  make  tests  of  specimens  of  the  same  specific  density  as  the 
street  material  employed,  by  means  of  Yicat's  standard  needle  of  1 
square  cm.  circular  cross  section. 

(d)  To  determine  the  wear  of  such  pieces  by  abrasion. 

(e)  To  determine  the  resistance  to  frost  of  those  specimens. 

D.  TESTS  OF  PRESERVATIVES  FOR  NATURAL  AND  ARTIFICIAL 

STONE. 

1.  The  tests  of  natural  and  artificial  building  stone  from  the  point  of 
view  of  their  preservation  should  be  made  by  tension. 

All  results  obtained  up  to  the  present  from  the  testing  of  preservatives  agree  in 
demonstrating  that  they  always  tend  to  produce  an  increase  of  strength,  or,  at  any 
rate,  a  diminution  of  the  loss  of  strength  caused  by  saturation  and  repeated  freezing. 
As  all  materials  used  for  preservation  form  surface  coatings  and  do  not  fully  per- 
meate the  stone,  it  appears  proper  to  employ  for  the  tensile  tests  test  pieces  of  small 
cross-sectional  area.  Great  size  of  surface  as  compared  with  volume  will  make  the 
action  of  preservatives  more  pronounced  and  is,  therefore,  an  additional  reason  for 
the  above  form  of  test  pieces. 


37 

2.  The  normal  German  standard  of  5  cm.  of  minimum  cross  section 
will  be  adopted  for  the  test  pieces. 

All  natural  building  stones  which  are  in  need  of  preservatives  being  soft,  there  is 
no  difficulty  in  giving  them  the  standard  form.  For  shaping  artificial  stone  the 
German  pattern  can  be  used. 

The  German  testing  machine  is  directly  adapted  for  the  tension  testa. 

3.  Three  specimens  are  sufficient  for  each  series  of  tests.     Where 
important  anomalies  are  found  five  additional  specimens  will  be  tested. 

4.  The  method  of  testing-  the  resistance  to  frost  prescribed  for  nat- 
ural and  artificial  stone  under  No.  VII,  B  a  and  No.  VII,  B  ft  will  also 
be  applied  to  the  testing  of  preservatives.     Besides  that,  tests  are 
recommended  for  the  purpose  of  determining  the  durability  of  the  pre- 
servative effect.     In  practice  it  may  be  sufficient  to  repeat  the  above 
tests  after  one,  three,  and  five  years. 

5.  There  may  exist  preservatives  the  action  of  which  consists  not  so 
much  in  increasing  the  strength  of  the  stone  as  in  protecting  it  against 
atmospheric  destructive  agents  through  obstruction  of  the  surface  pores. 
In  these  cases  the  apparent  porosity  should  be  determined  by  measur- 
ing the  capacity  of  absorption  of  uniform  test  pieces,  in  percentages  of 
their  weight,  before  and  after  having  been  treated  with  the  preservative. 

6.  The  application  of  the  preservative  material  to  the  test  pieces 
should  conform  to  the  method  in  which  that  product  is  used  in  prac- 
tice.   It  is  recommended  that  the  treatment  should  vary  according  to 
the  nature  of  the  preservative,  as  the  method  of  its  use  may  also  exer- 
cise a  considerable  influence  on  its  action. 

VIII.  TESTS  OF  HYDRAULIC  BINDING  MEDIA. 

A.  GENERAL  REMARKS. 

1.  When  it  is  a  question  of  binding  media  intended  for  a  given  pur- 
pose, the  test  should  be  made  with  respect  to  such  purpose  as  well  as 
with  respect  to  the  available  materials  used  in  mixing  (such  as  sand, 
gravel,  slag,  etc.).    Those  tests  must  not  be  replaced  by  those  known 
under  the  name  of  "standard  tests." 

Sewer  pipes  and  covers  should  be  tested  according  to  the  methods 
of  Professor  Bauschinger.  (See  Mittheilungen  aus  dein  mech.  tech. 
Laboratorium  der  tech.  Hochschule  in  Miinchen,  Heft  VII.) 

2.  The  tensile  and  compressive  strength  as  derived  at  present  from 
standard  tests  does  not  by  itself  furnish  conclusive  evidence  in  regard 
to  the  durability  of  structures.     This  is  influenced  to  a  very  great 
extent  by  other  important  factors,   such  as  resistance  to  weather, 
impermeability  to  water,  adhesive  strength,  and  constancy  of  volume. 
It  being  impossible  to  fully  utilize  the  strength  so  far  already  obtained 
for  cement  mortars,  it  does  not  appear  necessary  to  seek  to  increase  it. 


38 

B.  NOMENCLATURE. 

1.  Hydraulic  limes  are  products  obtained  by  the  calcination  of  lime- 
stones containing  more  or  less  clay  or  silicic  acid,  and  which,  sprinkled 
with  water,  are  slaked  entirely  or  partially  into  powder.    According 
to  local  cireumstances,  the  lime  is  delivered  in  commerce  in  the  form  of 
lumps,  or,  hydrated,  in  the  form  of  powder. 

2.  Roman  cements  are  products  obtained  by  the  calcination,  below 
the  verge  of  vitrification,  of  marl  containing  much  clay.    They  do  not 
slake  when  sprinkled  with  water,  and  it  is  necessary  to  employ  mechan- 
ical means  to  reduce  them  to  powder. 

3.  Portland  cements  are  products  obtained  from  the  calcination,  up  to 
the  verge  of  vitrification,  of  natural  marl,  or  of  artificial  mixtures  of 
substances  containing  clay  and  lime.    They  are  reduced  to  powder  by 
grinding,  and  contain  at  least  1.7  parts,  by  weight,  of  lime  for  1  part  of 
the  material  which  gives  to  tbe  lime  its  hydraulic  property.    To  regu- 
late certain  properties  of  technical  importance,  there  may  be  added 
foreign  material  up  to  2  per  cent  of  the  weight  without  this  addition 
necessitating  any  change  of  name. 

4.  Hydraulic  admixtures  are  natural  or  artificial  materials  which 
generally  do  not  harden  under  water  when  alone,  but  only  when  mixed 
with  caustic  limes.   Such  are  Pozzuolana,  Santorin  earth,  trass  obtained 
from  certain  volcanic  tufa,  furnace  slag,  burnt  clay,  etc. 

5.  Pozzuolana  cements  are  products  obtained  by  intimately  mixing 
powdered  hydrates  of  lime  with  hydraulic  mixtures,  ground  to  the  fine- 
ness of  dust. 

6.  Mixed  cements  are  products  obtained  by  intimately  mixing  manu- 
factured cements  with  suitable  admixtures.    Such  binding  media  should 
be  formally  designated  as  mixed  cements,  with  an  indication  of  the 
materials  entering  into  their  composition. 

O.  TESTS. 

1.  Weight. 

(a]  The  determination  of  the  specific  weight  of  hydraulic  binding 
media — that  is  to  say,  of  their  grains — will  be  made  uniformly  by  means 
of  the  so-called  volumenometer. 

(b)  For  the  determination  of  volume  weight  (or  apparent  density)  of 
a  hydraulic  binding  medium  there  will  be  used  a  standard  cylindrical 
vase  of  the  capacity  of  one  liter  and  10  cm.  in  height,  into  which  the 
material  will  be  passed,  as  follows : 

(a)  Passed  in  mechanically  through  a  sieve  by  means  of  a  Tetmajer 
apparatus. 

(/?)  Shaken  in  mechanically  by  means  of  a  Tetmajer  apparatus. 

(y)  Poured  in  by  hand,  making  use  of  a  funnel  apparatus  for  filling, 
and  of  the  standard  liter  vase. 

2.  Fineness  of  grain.     The  fineness  of  grinding  in  hydraulic  binding 
media  will  be  determined  by  means  of  screens  from  900  to  4,900  meshes 
per  square   centimeter   for  Portland  cement,  and   from  900  to  2,500 


39 

meshes  per  square  centimeter  for  the  other  hydraulic  binding  media, 
the  quantity  to  be  employed  for  each  test  being  100  grams.  The  wire 
of  the  screens  should  have  the  following  dimensions: 

For  screens  of  4,900  meshes,  2,500  meshes,  and  900  meshes  per  square 
centimeter,  the  diameter  of  wire  will  be  respectively  0.05,  0.07,  and 
0.1  mm.  It  is  recommended  always  to  employ  screens  from  the  same 
makers. 

3.  Conditions  of  setting. 

a.    FOR   ALL   HYDRAULIC   BINDING  MEDIA   EXCEPT   POZZUOLANA    (TRASS). 

(a)  The  study  of  the  conditions  of  setting  should  always  be  made  at 
a  temperature  of  from  15°  to  18°  0. 

(b)  The  investigations  should  be  made  on  a  paste  of  normal  consist- 
ency.    To  determine  that  consistency  there  will  be  used  the  standard 
needle  combined  with  the  consistency  measure,  which  is  composed  of  a 
rod  1  cm.  in  diameter,  with  a  weight  of  300  grams,  and  a  cylindrical 
box  8  cm.  in  diameter  and  4  cm.  high,  made  out  of  a  substance  imper- 
meable to  water  and  a  nonconductor  of  heat  (preferably  hard  rubber). 

To  determine  the  normal  consistency  there  should  be  mixed  400  grams 
of  the  hydraulic  binding  medium  with  a  certain  quantity  of  water,  so  as 
to  form  a  thick  paste,  which  will  be  worked  by  means  of  a  spatula  in 
the  form  of  a  spoon  for  exactly  3  minutes  for  the  slow-setting  cements 
and  for  1  minute  for  the  rapid-setting  cements.  This  paste  is  then 
placed  into  the  box  without  shaking,  and  after  smoothing  the  surface 
the  rod  is  cautiously  rested  on  it  and  allowed  to  sink  into  the  paste. 
The  consistency  of  the  paste  will  be  considered  a  standard  one  if  the 
progress  of  the  rod  is  arrested  at  a  height  of  6  mm.  above  the  bottom  of 
the  box. 

(c)  The  conditions  of  set  will  be  determined  by  a  standard  needle 
weighing  300  grams  and  having  a  circular  section  of  1  square  mm.,  and 
with  the  same  box  as  above. 

Four  hundred  grams  of  the  binding  medium  to  be  tested  are  mixed 
to  a  paste  with  the  quantity  of  water  previously  determined,  as  shown 
under  &,  the  duration  of  working  the  paste  being  (as  under  b)  3  minutes 
for  slow-setting  and  1  minute  for  quick-setting  binding  media;  then  the 
paste  is  filled  into  the  box  as  above. 

Hardening  has  commenced  when  the  needle  can  no  longer  completely 
penetrate  the  material.  For  rapid-setting  material  the  commencement 
of  hardening  can  also  be  determined  by  means  of  the  thermometer. 

To  determine  the  duration  of  set  the  box  will  be  turned  over.  All 
hydraulic  binding  media  may  be  considered  as  having  set  when  the 
standard  needle  no  longer  leaves  any  imprint  on  the  cake  of  mortar. 
The  time  necessary  to  obtain  that  result  is  termed  the  "  duration  of 
set." 

The  designation  of  hydraulic  binding  media  as  quick  or  slow  setting 
is  governed  by  the  commencement  of  hardening. 

(d)  The  following  test  maybe  made  preliminary  to  the  determination 


40 

of  the  duration  of  set.  There  are  mixed  100  grams  of  the  cement  to 
be  tested  with  the  water  necessary  to  form  a  paste  of  normal  con- 
sistency, which  is  worked  for  3  minutes  or  1  minute,  according  to 
\vhether  the  material  is  slow  setting  or  quick  setting,  and  then  spread 
on  a  glass  plate  in  a  cake  about  2  cm.  thick.  This  cake  may  be  con- 
sidered as  set  as  soon  as  it  resists  a  slight  pressure  of  the  finger  nail. 

(e)  Besides  testing  the  conditions  of  set  with  pastes  of  standard 
consistency,  it  is  desirable  that  they  should  also  be  tested  with  paste 
prepared  with  greater  quantities  of  water. 

/?.    FOR   POZZUOLANA    (TRASS). 

Pozzuolana  reduced  to  fine  powder  and  dried  at  a  temperature 
between  100°  and  110°  C.  is  tested  from  the  point  of  view  of  the  loss  of 
water  of  crystallization  by  calcination,  and  from  the  point  of  view  of 
the  commencement  of  hardening  under' water,  by  means  of  a  normal 
needle  of  300  grams  with  a  circular  section  of  1  square  millimeter. 
(See  above  under  a  c.)  This  last  test  is  made  as  far  as  possible  at  the 
temperature  of  15°  C.;  at  any  rate  a  record  of  the  temperature  will  be 
kept,  the  mixture  used  for  the  test  being  2  parts  by  weight  of  Pozzuo- 
lana, 1  part  by  weight  of  hydrate  of  lime  in  powder,  and  1  part  by 
weight  of  water.  This  mortar,  filled  into  the  box  and  smoothed  off, 
will  be  immediately  submerged  in  water  and  tested  after  two,  three, 
four,  and  five  days  to  determine  the  weight  under  which  the  above 
standard  needle  will  completely  penetrate  it,  the  box  used  not  being 
higher  than  4  cm. 

4.  Constancy  of  volume. 

(tv)  Portland  cement. 

(a)  To  determine  rapidly  the  constancy  of  volume  of  Portland  cement 
when  hardening  in  water  or  under  conditions  preventing  it  from 
becoming  dry  the  following  test  is  recommended: 

The  cement  is  mixed  with  water  to  a  paste  of  standard  consistency 
and  then  spread  on  a  plane  thin  glass  plate  so  as  to  form  cakes  of  from 
8  to  10  cm.  in  diameter  and  about  2  cm.  thick.  Two  of  those  cakes, 
which  must  be  protected  against  desiccation  to  avoid  cracking,  are 
placed  after  24  hours,  but  under  no  circumstances  before  they  have 
set,  on  a  metallic  plate,  plane  side  down,  and  submitted  to  a  tempera- 
ture from  110°  to  120°  0.  until  evaporation  ceases  (but  at  least  for  1 
hour). 

If  after  that  operation  the  cakes  show  neither  warping  nor  cracks 
on  the  edges,  the  cement  may  be  considered  as  possessing  constancy 
of  volume ;  otherwise  recourse  must  be  had  to  the  cake  test  on  glass 
plates,  which  is  at  present  universally  employed  and  considered 
decisive. 

The  presence  of  more  than  3  per  cent  of  anhydrous  sulphate  of  lime 
(or  the  corresponding  portion  of  unburnt  gypsum)  will  prevent  the 
above-described  test  from  being  conclusive. 


41 

(b)  The  decisive  test  for  constancy  of  volume  is  that  of  the  cakes 
on  glass  plates.     It  is  made  in  the  following  manner: 

One  hundred  grams  of  the  cement  to  be  tested  are  mixed  with  water 
to  a  paste  of  standard  consistency  and  then  spread  on  a  plane  glass 
plate  into  a  cake  2  cm.  thick.  Two  cakes  thus  obtained,  and  protected 
against  desiccation  to  avoid  cracking,  are  placed  in  water  after  24  hours, 
but  certainly  not  before  having  set.  The  cement  tested  may  be  con- 
sidered as  possessing  constancy  of  volume  if  at  the  end  of  28  days  the 
cakes  do  not  show  any  warping  or  cracks  on  their  edges. 

(c)  The  boiling  test  may  undoubtedly  be  considered  as  the  most  con- 
clusive and  rapid  test  for  the  determination  of  constancy  of  volume  of 
Portland  cement,  of  slag  cement,  and  of  trass. 

The  boiling  test,  as  described  below,  has  been  referred  to  the  subcom 
mitteefor  examination  and  report. 

Fifty  grams  of  the  cement  to  be  tested  are  mixed  to  approximately 
standard  consistency — that  is,  with  13  to  15  grams  of  water — and  after 
having  been  worked  for  1  minute  are  spread  on  a  glass  plate  into  a  cake 
1  cm.  thick  in  the  middle  and  thinning  out  toward  the  edges.  This  cake  is 
kept  for  24  hours  in  a  covered  receptacle,  saturated  with  steam,  then  placed, 
either  after  having  been  detached  from  the  glass  plate  or  together  with  it, 
into  a  bath  of  cold  water,  which  is  slowly  brought  to  the  boiling  point — that 
is,  say,  in  about  10  minutes — the  lid  being  kept  on  in  order  to  reduce  evapo- 
ration. The  cakes  should  be  entirely  submergedin  the  boiling  water;  ichen 
any  water  has  to  be  added,  this  should  be  done  in  small  quantities,  so  that 
the  boiling  point  is  quickly  restored. 

It  is,  moreover,  recommended  to  the  permanent  committee  to  consider 
also  the  mixtures  of  cement  and  sand  in  their  investigations  of  methods  for 
determining  constancy  of  volume. 

From  the  experiments  of  Professor  Bauschinger  it  was  found  that  cements  which 
had  given  favorable  results  by  the  "standard-cake  test"  (see  above  under  b)  not 
only  after  28  days  but  also  after  six  months  and  a  year  would  fail  when  mixed  in 
thti  proportion  of  1  to  3  and  formed  into  prisms  of  5  square  cm.  cross  section  and  12 
cm.  length ;  expansion  was  perceptible  after  six  months  in  Bauschinger's  apparatus 
and  after  a  longer  period  also  with  the  naked  eye. 

(#)  Hydraulic  limes  and  Koman  cements: 

(a)  For  those  materials  the  cake  test  under  water,  described  before 
under  a,  b  is  recommended. 

(b)  The  study  of  the  boiling  test  (see  under  a,  c)  has  been  assigned  to  the 
permanent  committee. 

(y)  Pozzuolana  (trass). 

(a)  For  these  the  following  method  is  recommended:  A  mixture  of  2 
parts  by  weight  of  Pozzuolana  (trass),  1  part  by  weight  of  hydrate  of 
lime  in  powder,  and  1  part  by  weight  of  water  is  placed  into  a  strong 
metallic  box  (say  of  galvanized  iron)  open  at  the  top,  slightly  conical 
in  shape,  from  3  to  4  cm.  in  height  and  from  6  to. 8  cm.  in  diameter  on 
top;  after  the  mixture  has  been  leveled  off,  the  box  containing  it  is 
immediately  placed  into  a  receptacle  full  of  water,  so  that  the  upper 
edge  of  the  box  is  submerged  to  a  depth  of  2  cm.  The  hardening 


42 

mortar  should  neither  rise  above  the  edges  of  the  box  nor  should  it 
swell  in  the  middle,  arch-like.  The  bottom  of  the  box  should  be  solid, 
in  order  that  the  mortar  may  expand  upward  only. 

(b)  The  boiling  test  may  undoubtedly  be  considered  the  most  reliable 
and  the  most  rapid  test  for  determining  constancy  of  volume,  even 
when  the  material  is  trass  (see  above  under  a  c). 

5.  Tests  of  strength. 

(a)  For  all  hydraulic  binding  media  with  the  exception  of  Pozzuo- 
lana: 

(a)  The  tests  of  strength  will  be  made  on  a  mixture  of  1  part  by 
weight  of  the  binding  medium  with  3  parts  of  sand.     It  is  desirable, 
however,  that  tests  should  also  be  made  with  greater  admixtures  of 
sand. 

(b)  The  sand  employed  should  be  standard  sand  obtained  from  quartz 
sand>  as  nearly  pure  as  possible. 

The  official  standard — that  is  to  say,  the  sand  to  which  all  compari- 
sons are  referred — is  Freienwalde  sand  which  passes  through  a  sieve  of 
60  meshes  and  is  held  by  one  of  120  meshes  per  square  centimeter. 

For  other  countries  outside  of  Prussia  it  is  optional  to  procure  their 
own  standard  sand,  selecting  it,  however,  if  possible,  so  that  its  influ- 
ence on  the  strength  of  mortar  is  the  same  as  that  of  the  standard 
Freienwalde  sand.  Where  that  is  impossible,  judicious  coefficients  of 
comparison  should  be  determined. 

(c)  The  wire  diameters  of  the  above  sieves  should  be  as  follows: 
Screen  of  60  meshes,  0.38  mm.  in  diameter;  screens  of  120  meshes, 
0.32  mm.  in  diameter. 

(d)  The  volumetric  weigh t^of  the  standard  sand  will  be  determined 
by  means  of  the  standard  liter  into  which  the  sand  is  passed  from  the 
sieves. 

(e)  The  decisive  test  of  strength  is  the  compression  test.     It  is  made 
on  cubes  5  square  cm.  in  section. 

(/)  The  ordinary  test  of  quality  (the  test  controlling  the  delivery  of 
materials)  is  the  tension  test  made  by  means  of  the  standard  German 
apparatus  on  test  specimens  of  German  standard  form  with  a  cross 
section  of  5  square  cm. 

(g)  The  determination  of  standard  consistency  of  mortar  and  the  search 
for  a  suitable  mechanical  method  of  malting  test  pieces^  especially  with  a 
view  of  obtaining  equal  density  of  the  test  pieces  for  tension  and  compres- 
sion^ remains  referred  to  the  permanent  committee. 

For  the  present,  test  pieces  for  tension  and  compression  may  be  made 
by  hand,  but  as  far  as  possible  of  the  same  degree  of  density. 

(h)  To  determine  resistance  to  tension  and  compression,  six  test 
pieces  of  equal  age  are  required  for  each  series.  The  arithmetical 
mean  of  the  four  highest  values  obtained  will  be  considered  as  conclu- 
sive. 

(i)  All  test  pieces  must  be  kept  for  the  first  24  hours  in  a  receptacle 
saturated  with  steam  j  after  that,  and  up  to  the  time  of  testing,  they 


43 

will  be  kept  submerged  in  water,  the  temperature  of  which  ranges 
from  15°  to  18°  0.,  and  which  will  be  renewed  every  7  days. 

(A*)  The  28-day  test  is  considered  conclusive  for  all  binding  media. 

To  judge  of  the  quality  in  a  shorter  time  there  may  be  determined  in 
the  case  of  Portland  cement  the  strength  of  a  mixture  of  1  to  3  after  7 
days. 

Concerning  the  determination  of  quality  in  a  yet  shorter  time,  viz, 
in  3  days,  the  convention  of  Vienna  has  decided  upon  the  following: 

The  tests  of  neat  cement  (Portland  cement  and  slag  cement)  are  not 
sufficient  of  themselves  to  give  exact  information  concerning  those 
products. 

The  test  pieces  obtained  by  the  use  of  normal  sand  in  a  proportion, 
of  1  to  3  do  not  offer ,  it  is  true,  a  basis  sufficiently  certain  for  judging 
of  the  exact  value  of  Portland  and  slag  cements,  but  they  allow  the 
formation  of  an  approximate  opinion  on  the  quality  of  those  materials, 
and  for  this  reason  the  introduction  of  the  3-day  test  is  recommended. 

In  this  connection  the  convention  recommends  that  there  should  be 
employed  for  the  manufacture  of  test  pieces  only  such  machines  as  will 
allow  the  making  of  tension  and  compression  specimens  as  nearly 
simultaneously  as  possible  and  with  the  standard  amount  of  ramming. 

The  standard  sand  employed  must,  of  course,  be  pure  quartz  sand. 

For  the  determination  of  compressive  strength  there  should  be 
employed  machines  of  precision. 

The  permanent  committee  remains  charged  with  the  elaboration  and  sub- 
mittal  of  short-time  tests  of  quality  for  the  other  hydraulic  binding  media, 
special  attention  to  be  paid  to  chemical  analysis.  Consideration  of  the 
needle  test  iy  this  connection  (determination  of  the  weight  under  ivhich  a, 
needle  or  a  piston  will  penetrate  to  a  given  depth  into  the  binding  medium 
when  in  the  process  of  hardening)  as  well  as  of  the  influence  of  warm  baths 
on  the  acceleration  of  hardening  will  also  be  given. 

(ft)  The  tests  of  strength  of  mortar  from  Pozzuolana  (trass)  should 
be  made  uniformly  on  a  mixture  of  2  parts  by  weight  of  the  Pozzuolana, 
1  part  of  hydrate  of  lime  in  powder,  3  parts  of  standard  sand,  and  1  part 
of  water.  The  manipulation  should  be  the  same  as  for  cement,  notably 
as  far  as  the  preservation  for  24  hours  in  air  in  a  room  saturated  with 
humidity  before  immersion  under  water  is  concerned.  For  certain 
special  uses  the  samples  may  be  immersed  immediately  after  their 
preparation.  In  such  cases  the  quantity  of  water  entering  into  the 
composition  of  the  mortar  should  be  increased  by  one  tenth.  Observa- 
tion of  the  temperature  conditions  is  of  the  greatest  importance  for  all 
Pozzuolana  mortars ;  if  at  all  possible  there  should  be  employed  water  at 
a  temperature  of  from  15°  to  18°  C.  for  the  preparation  and  immersion 
of  the  test  pieces.  There  should  be  employed  for  the  test  of  Pozzuolana 
mortars  only  the  pure  lime  coming  from  marble,  since  the  strength  of 
the  mortar  depends  a  great  deal  upon  the  lime. 

Where  the  managers  of  works  of  construction  produce  their  Pozzuo- 
lana (trass)  themselves  from  tufa,  the  rock  from  which  the  samples  for 


44 

testing  are  to  be  taken  will  be  powdered  sufficiently  fine  to  allow  75  per 
cent  of  it  to  pass  through  a  sieve  of  900  meshes,  and  50  per  cent  to  pass 
through  a  sieve  of  4,900  meshes  to  the  square  centimeter,  the  thickness 
of  wire  being  as  given  above. 

During  the  process  of  powdering  coarse  particles  must  not  be  thrown 
out,  but  the  process  must  be  continued  until  the  entire  quantity  has 
been  reduced  to  the  requisite  degree  of  fineness. 

6.  Adhesive  strength.     The  devising  of  satisfactory  methods  of  test,  in 
which  will  be  employed  as  far  as  possible  the  normal  German  apparatus 
for  tests  of  tensile  strength,  remains  referred  to  the  permanent  committee. 

7.  Density.     This  may  be  determined  either  by  means  of  the  well- 
known  mortar  volumenometer  or  by  a  calculation  according  to  StahPs 
method.    (See  for  a  description  of  that  method  No.  14  of  Mittheilungen 
aus  dem  mech.  tech.  Lab.,  etc., pp.  252-270.) 

8.  Action  of  sea  water  on  hydraulic  binding  media.     In  consequence 
of  a  paper  read  by  Professor  Debray  at  the  Berlin  convention  the  per- 
manent committee  was  instructed : 

To  study  the  action  of  sea  water  on  hydraulic  binding  media. 

When  the  report  on  this  subject  was  submitted  to  the  Vienna  con- 
vention opinions  were  found  to  differ,  even  in  regard  to  the  form  of  the 
test  pieces  and  the  methods  of  test.  The  question  was,  therefore,  once 
more  referred  to  the  subcommittee,  which  was  instructed  to  adopt  its 
own  methods  of  test  and  to  take  into  consideration  also  very  poor  mixtures 
with  fine  sand. 

Besides  the  old  questions  indicated  herein  by  italic  characters  as 
having  been  sent  back  to  the  fourth  permanent  committee  by  the  con- 
vention of  Vienna,  the  following  questions  were  also  submitted  to  it: 

Determination  of  the  methods  of  testing  materials  of  construction,  nota- 
bly iron,  with  respect  to  its  behavior  when  exposed  to  exceptionally  low 
temperatures. 

Determination  of  the  influence  of  fecal  matter  on  hydraulic  binding 
media. 

Study  of  abnormal  behavior  of  cements,  notably  concerning  time  of  set. 

Whereas  the  unification  of  methods  of  testing  is  of  great  technical  and 
commercial  importance,  not  only  for  materials  of  construction  in  the  Strictest 
sense  of  the  word,  but  also  for  other  raw  materials  and  manufactured  prod- 
ucts; and 

Whereas  it  is  hardly  practicable  to  strictly  define  the  limit  of  the  expres- 
sion "materials  of  construction;"  and 

Whereas  several  of  the  institutes  and  experts  who  have  taken  part  at  the 
convention  possess  great  experience,  not  only  in  testing  materials  of  con- 
struction, but  also  concerning  technical  researches  on  textile  fabrics,  paper, 
€tc.,  now, 

Be  it  resolved,  that  the  permanent  committee  is  instructed  to  consider 
whether  and  in  what  manner  the  future  conventions  can  arrive  at  an  agree- 
ment on  uniform  methods  of  testing  substances  and  products  of  technical 
importance. 

C 


*  ctmpniet 

Binder 
Gaylord  Bros..  Inc. 

Stockton,  Calif. 
T.  M.  Reg.  U.S.  Pat.  Off. 


YC 


TA4o<=> 


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